Information in Atom Program

[Irini Mastoraki]

Dear all,   Has anyone ever used the atom program to design crystallographic or magnetic structure?       I have a difficulty at this time in the way we define the octahedra or tetrhedra in a crystallographic structure.Also I would like some advise upon how we can define a specific number of atoms or else how we can design only one unit cell in a structure.   Moreover regarding the magnetic structure is there a possibility to draw the moment's vectors?   Provided that the answer on the above questions is very extensive I would be very grateful if someone could provide me a reference to look at.   Many thanks  in advance,   Irini