How do I setup product combinations?

What are "Product Combinations"?
This feature allows you to set options and customize products whether it's the color of a chair, the size of a shirt or custom text for a mug with engraving options. Please refer to the article below for details on how to set options for products in your store: Product Options
We would like to present the next step beyond options: Product Combinations. Product combinations gives your clients the power to choose and keeps pace with your inventory! While Product Options delivers on giving your specified orders until it comes to tracking inventory or when you need to change main product image depending on the selected options (frequently used for apparel and shoes). All of these scenarios require "Product Combinations".
Product combinations is a product with one or more selected options. This could have its own price, weight, picture, quantity and even SKU. Product combination inherits the image, price, weight and quantity values from the main product by default. However, you should set an unique combination SKU as soon as you changed one of its significant parameters (price, weight, quantity), which is logically correct once you get a completely different item.
The combinations don't count towards product limit of your store's subscription plan. Yourshop can contain any number of product combinations.
How product combinations work?
Every item in the store has a base combination, which is technically the main product with no parameters selected.
Base combination's price, image, SKU and quantity matches up with the main product values. Product Combination is created when a product with a particular set of options should have it's own price, weight, quantity or image. There is no need to create combinations of all available products options, since an existence or lack of the combination will not affect product availability. In other words, if a product with selected options doesn't match any created combinations, it will be considered as a product without combinations at all (as if no combinations were created for this item).
Imagine that you sell footballs and some of them have an autograph of famous football players. This product will have the following list of options:
You only have three autographed footballs -- two blue and a red one. You should only track the autographed inventory to prevent overselling. At the same time, you don't need to track the inventory of footballs without autographs. From here, you will get the following combination setup:
According to above settings, The Webydo Store will search your inventory for the combinations by processing all available combinations from top to bottom. If available, the first matching combo is applied. Otherwise, the base combination will be chosen.
When Any is listed as the value within the "gift wrap" option, all created combinations are shown. Any should be chosen in all cases where the parameters are unknown or unnecessary. In our example, we are tracking number of footballs with an autograph. Thus, even though we need to know the football's color (remember, that we have particular number for each color), the "Gift wrap" option value is not necessary.
Any parameter value usage allows a merchant to set only two combinations: (Signed - Red - Gift Wrap (Any) and Signed - Blue - Gift Wrap (Any)) instead of four (Signed - Red - Gift Wrap (Yes) and Signed - Blue - Gift Wrap (Yes), Signed - Red - Gift Wrap (No) and Signed - Blue - Gift Wrap (No))
Product combination doesn't remove the price modifier setting for the option included in this combination. Price modifier will be added to the base product price (or product combination's price if it was set) as usual. We don't recommend using price modifier and combinations with separate prices simultaneously as they complicate the system together.
Also, draw attention to Signed - Green - Gift Wrap (Any) combination that is marked as "Out of stock". This combination type is essential when combination of options doesn't exist or can't be sold for some reasons (It our example, we just don't have green football with autograph)
Here is a screenshot of an example product with different options selected:
Not Signed Ball without Gift Wrap
Signed Ball Without Gift Wrap
Signed Ball with Gift Wrap
Signed, but out of stock
How to create a combination?
Let's examine product combinations in a few examples:
Example 1
Imagine your apparel store: there are several t-shirts with different sizes and colors. The colors and sizes are limited to what you need to track the inventory for each color and size separately to avoid overselling. Thus, you should not only create options "Size" and "Colour", but also add the combinations of these options that allow you to track the inventory for each of these combinations. This can be done in several easy steps:
1. Open product modify page and switch to the "Options" tab: 
2. Create "Color" and "Size" options and add selections values for them: 
You can use the "Drop-down menu" and "Radio button" options to create combinations
3. Switch to "Combinations" tab and click the "New Combo" button. Choose "Color" and "Size" values in the popup window and set the quantity. You can also upload custom combination image and a sale price 
4. Repeat step 3 until all required combinations are created
You should also create the combination that doesn't exist or can't be sold for some reasons. All these combinations should be marked as "out of stock" (quantity is set to 0)
5. Set default product combination. It will be shown on the product details page by default.
Default combination is the combo created with default options' values. For example, if the "Size" option has "S" value selected as a default and the "Color" option has "Red" value selected as a default, than the combination with Size = S and Color = Red will be treated as a default.
Here is an example of product with default combination: 
Example 2
You sell photos and poster with different sizes. Based on the size, the price of these items varies. In addition, you want to offer framing. Here is the variant of such product combination settings:
What if I don't need all product combinations?
You should create all combinations anyway and mark combos that can't be sold in your store as "out of stock". From here, you may select "any" as the value to merge several combos into one.
Can I use the same SKU for a product and its combination?
If you don't need to track inventory for this combination separately, yes. Once you change a combination's quantity or another significant parameter (price, weight), Webydo will ask you to set a unique SKU for this combo. We base such a logic on a reasonable presumption: if a combination has its own inventory, it is treated like a separate unique item. For this reason, the combination should have a unique SKU.
Are combinations with unique SKUs count towards the store's product limit?
No. Webydo counts the number of unique items added to the store only (i.e. the number of items show on the Products Page). Each store item can have any number of combinations and it will not count towards the store's products limit.