Tracing shapes and characters

I've been searching for some time now for a tutorial that would guide me through the steps to create a finger tracing feature that would allow a user to learn how to draw letters, numbers, shapes etc similar to Alphabet Board Game.

So I need to be able to guide the user from each stroke to the next and not allow the next stroke in sequence to start until they have completed the first.

I have seen some people say colliders are the way to do it?

Thanks for any pointers, or tutorials