When a physical interface is configured for frame relay, the router assumes that all the PVCs/DLCIs (coming from the frame switch) belong to that physical interface.
When we create a multipoint sub-interface, and create a frame map there, the frame map lets the router know that the DLCI listed in the frame map is associated with that specific multipoint sub-interface.
When we create a point-to-point sub-interface, we don't create frame maps, but still need to let the router know that the point-to-point interface will be associated with a specific PVC/DLCI, and to do that we would use the frame-relay interface-dlci command, in that point-to-point sub-interface.
Hope that helps,
Frame relay does work in PT but is limited. Probably it is enough for CCNA level exam.
GNS3 is emulator that closely reflects FR operations and behavior. If you realy wanna be as close as possible, get GNS3 and IOS as GNS3 runs on real IOS.
see more at gns3.net