Newbie: Custom League w/ real players

Hello, I watched a video regarding downloading the historical roster mods, but not sure how to do the following:
- Create a custom fantasy team (about 10-12 teams)
- Draft 2020 Real Players
- Manager all teams versus just 1
Any suggestions? Thank you!
- Create a custom fantasy team (about 10-12 teams)
- Draft 2020 Real Players
- Manager all teams versus just 1
Any suggestions? Thank you!