What is the reason I cant connect feature with one or multiple products?

This is giving me a hard time.

Whenever I want to create a certain filter the matching of imported features just wont work. Sometimes I just try the most top down category but still it wont appear .
In the future I need to do this thru import for mass adoption but even manually it is giving me a hard time. I wish there was a walk thru or video but community seems to small atm.

my main questions are:

1.) how to connect any feature I like to any product or group I like?
2.) I know filters only appear if it find a connected value but when does filter not appear at all and why? Always try the top category to get every subcategory below. I think it is vice versa though?!
3. A product import with feature parameter like this brand: S (Nike) will not guarantee creating variants? Why not?
I actually treid to import new variants thru variation import but it wont do. It worked better for the feature import though yet my feature wont show up anywhere although being linked to certain categories.
4. Sometimes it is impossible to find the feature to add a value.

I put so much times into this

Hello

For first point maybe this solution will useful for you?

Best regards
Robert

Thank you but in general. If I want to connect products from certain categories to one or more features then all it takes is adding the top category (will include all subcategories) and then make it selectable on product feature tab to connect values to them.

The biggest bug from CScart is that they display every single non sense feature to the edit page. Thousands of irrelevant features.