What is the purpose of external terminals on a logic probe?
The connector is just connected directly to the main probe, but some of the attachments are easier for certain things than others. There is one which is an alligator clip, and the other one is a hook probe. If you press the bottom of the hook clip, you should see a small metal hook slide out of the top. You can put a lead or wire through it, then release the bottom, and the hook will retract, clamping the lead or wire under it.