For detailed, printable versions of the user manual, please check dedicated resources such as the Baofeng download area or community-driven documentation sites like Miklor.
Your squelch level (Menu 0) might be set too low, or you have accidentally enabled an incorrect CTCSS/DCS code (Menus 10-13) that is filtering out incoming audio. Turn tones off to test. Baofeng Uv-8r Manual