Introduction to testing. Where to begin?

Question

Software testing

Good afternoon! Tell me where to start and how to continue studying the specialty "tester". I started with the free part of the Yandex course, but I don’t know how to move on and what I need to study to fully master the profession. Can you tell me some free courses (maximum inexpensive), literature and in general what knowledge is enough to start working in this field of activity. Thank you all in advance!

Answer 1

See here Course from Mikhail Portnov, the creator of the school of testers in Silicon Valley.

Answer 2

https://github.com/anas-qa/Quality-Assurance-Road-Map