I can try to help you for few commands. First of all you need to create an unattached Flat (first wall) to start. Then you can add features to that flat wall. Like you can use Flat command (this creates a secondary wall) to attach a wall of desired shape (in 2D. It needs closed sketch as required to create first wall.) at the edge of earlier created flat. Flange allows you to attach a wall with certain cross section (in 1D only. It needs open sketch). To use flat and flange features you must have an unattached flat.