If you want to do manual testing:
1. Go to github looking for some more or less large application for andoid
2. Understand how github works / Assembly applications
3. Write a letter to the developer that you are ready to test the app for free and for the experience.
4. Choose testing tools, where you will fight logs and write test cases
5. Start writing test cases and do other tedious document work (only English, forget Russian)
For a month or two you get enough experience for a job.
Search the app in Google Play there is no need. All normal - enough optimized and tested not once, not twice