Step 1. Decide how many sockets the outlet should have, and its orientation. It'll tell you the kind and number of frames required.

Step 2. Clarify the role of each outlet on the frame, e.g. electrical socket, audio, usb etc. It'll tell you the kind and number of inserts required.

Step 3. Depending on what you have so far after step 2, you need to add connectors and switches.

Step 4. Some special purpose connectors and inserts require a cover on them as well