switching to another ruby version

hello guys i have issue like this , i download some rails projects from github and run server but in every situation ruby version missed the project was old or not comparable with my ruby version , so i want to know if there is any tool for switch ruby version without downgrade or reinstall , i'm begginer with rails (also using Windows
:/ )

use rvm . it could manage multiple ruby versions.

https://rvm.io/

You could also use rbenv https://github.com/rbenv/rbenv which I personnaly prefer, that said, RVM does a fantastic job too !