Carciphones_02 Well the easiest would be to make an author note at the end of your book and say "Hello I need a beta reader. Are you interested in reading the chapters before anyone else, then contact me on XX (this could be your discord, or your email or whatever you are confident with sharing)
I request my beta readers to reply to me every time they read a chapter, and tell me what they think of it. Some of them just says "it was good," and only comments in depth if they find errors, and others comment on every chapter, in detail about every single thing, like "this flows good," "this sentence feels a bit stiff, rewrite it," and so on.