Parasolid core - Creating work plane

Hello! Trying to create a lighter version of CAD (we are students of a technical college) for training purposes on the core Parasolid. There was a problem with the creation of the plane, and more specifically how to use tools to create parasolid work plane to draw the sketch. If you can, please explain how it is implemented, and what objects Parasolid contribute. Now we draw on the  Sheet but it's probably wrong. Thank you.