Hello fren, thanks for your comment!
The process of making cards will be reworked to provide a much better UX, the current format of dropdown lists was just a quick way of having it up and running but it will be worked into something much smoother and friendlier for sure. To answer your question, the green buttons on that screen are just confirm buttons, so you "lock-in" abilities when you click them, the catch is that you also need to lock in the activation timing for it to be added to the card, or skip that ability altogether if you leave it as -N/A-. Also minions only have access to 1 active ability, so that's why you skip directly to Passives after confirming the first active ability.
As I mentioned in Edengrall's dev comment, the mechanic of having each ability be a drop that you then use to craft is how it originally worked and how it still works in Adventure mode. I made it more accessible by just giving the user every ability as an option but this will likely change to having access to a random pool of abilities as you enter each forge. In fact, behind the scenes whenever you enter a forge in Castle Raid mode, the game gives you one of each crafting stone so you have access to all the abilities and timings.
UX for combat is a real piece of work, I'm doing my best to improve it with each update, next one will remove having to enter "Start of combat" and then press space again to enter "Attack" and instead just making you go straight to attack if no triggers automatically happen at the start of combat.
I would love to embed that sort of image generation to complement the "randomness" concept I'm going for, but doing so is just completely unviable and far beyond my abilities. At any rate, modding of images is extremely easy only requiring you to drop your images on a each of the 6 colors' folders, so at least there's that.
Thanks for your feedback and your time!