>>16743827
It's hard to recommend books because anons have all sorts of different backgrounds.
One of my favorite self-learner-level starter books is Susanna Epp's "Discrete Math with Applications".
It's not laser focused on your interests, but it does include some of the basics while providing a gentle introduction to more rigorous mathematical thinking. Please do give it a look, and apologies in advance if I've underestimated where you're at.

A more general tip for reading: It's an unspoken assumption of most mathematical authors that you will be reading their proofs and/or examples carefully and critically, and puzzling out the fine details of any steps you're unsure on (as in, with a pencil and paper). So even once you find a book that matches your level, you should expect to have to wrestle with it a little.