Minecraft Versions Files

1. So i been tring to go back to older versions of minecraft and newer but when i go to create a new version ther is only 1.16.3 , 1.16.2 , and Forge 1.12.2
2. I tride deleting minecraft and it still did not work.
3. The versions are not showing up now
4. now only 1.12.2 forge.
5. What do i do i cant play minecraft only 1.12.2