Mauricio,

>>>>>I’ve been trying all as said in the tutorials and help, and still don’t get how to do it, I’ll keep trying

Actually it is not very difficult in your case.
You already have profile in your drawing, all you need is to create closed polyline from it, then use REVOLVE command to create revolved 3D Solid.

I've done this in a few minutes. The resulting STL is in the attachment.