Hi ,
Welcome to Mendix World.
Since you are starting ,The following learning path will guide you to learn Mendix basics
https://academy.mendix.com/link/path/40/Mendix-Basics
After that , you can start learning the Rapid Developer Learning path
https://academy.mendix.com/link/path/31/Become-a-Rapid-Developer
I would start with https://academy.mendix.com and in the least do the crash course.