I spend some time to learn how to do models with FreeCAD. And it took me not a lot of time to get shape I wont (using Part or Part Design workbench). The only problem that took me lot of time was a colour problem - to have more than one colour in my models. With models defined using Part my problem was solved by switching from 0.18 to 0.19 FreeCad version. But with Part Design colours liked to disappear when exporting to STEP. At that moment I don’t remember exactly what problems I had (I am 60+ and sometimes have to learn few times the same specially if when problem is solved I use my solution only once and then do other things for several months). The last problem I had when I wonted to define a part as an array of one block (terminalblocks). The moment I have solved it (with forum members help) is here:
I hope that thread give you the solution for the most important problem I had when learning to use FreeCAD. Since those time I didn’t touched FreeCAD.