Moho Forum

Wow. Making 3D objects is a full time job in and of itself. It takes a lot of work to be a good modeler. There are sites that offer either free or very affordable objects/models already. Unless you're really serious about wanting to learn to model. In which case, you'll need 3D modelling software. You could find some free ones (Blender, Scultptris, etc...) or you could spend a small fortune for one (3DS Max, Maya, etc...)

There's a tutorial that comes with the program for how to make a basic cube. This could be used to make a building or a room interior. Something more complex like a car will probably require an outside program to model it, unless you do something simple like draw and extrude in Anime Studio, but that wouldn't be terribly detailed.