I'm going to assume you want to make functional models to be 3D printed.
Where to get it: www.freecad.org
FreeCAD goes through a somewhat rapid development compared to those making tutorials for it; however, the 'How to do X" doesn't change that often. It's important to remember that if you are having a hard time doing something, you are probably trying the wrong way.
CAD is like any other skill; you need to practice to get better at it.
Start learning
YouTube is about the only place you can learn to do anything for free, SO here we go.
MangoJelly Solutions
FreeCAD 1.1 Beginner Crash Course | From Zero to 3D Print
Mango has other tutorials for more advanced features.
CAD CAM Lessons
FreeCAD Tutorial 2026: 3D Modeling for Beginners