Alamak, this means that I lectured poorly and I didn’t manage to explain the ideas clearly, so let’s try again.

SoC: Try to figure out what are the things you care about and try to think about them separately. Some things can be separated, i.e. logic vs presentation, others cannot, i.e. performance

Abstraction: Information hiding. Hide stuff that people shouldn’t need to see to avoid confusing them.

Decomposition/Modularity: Break the problem done into smaller bitesized chunks so that each of them are smaller and easier to solve. What you have to worry about is the interactions between these pieces.

I hope this helps.