Before an official Fedora release comes out, a Beta pre-release is made. Beta and Final (GA) are the milestones for a Fedora release. At each milestone, nightly and 'candidate' composes are built and tested to ensure the build finally released as the Beta or final release meets certain requirements.
This document describes how this testing is carried out. You can contribute by downloading the nightly composes and candidate builds and helping to test them.
Testing will involve executing test cases to verify installation and basic functionality on different hardware platforms for the various Fedora products. Everyone is encouraged to test and share your ideas, tests, and results.
See the official website.
