In SelfCAD we have two types of objects - meshes and profiles. The basic difference between them is that meshes are composed of polygons and profiles are actually sets of edges. It means that the profiles have no volume and you cannot print them but you can use them to model many interesting printable meshes.
a) How can I create a Profile?
You can create profiles either by drawing them yourself in 3D Sketch or since each profile is composed of edges, you can easily copy them from the already ready mesh.