Tip = get a male "lucar" spade connector
and fasten a bit of wire to it.
Then, at the front of the relay panel you will see lots of unused receptacles (slots). Using your meter you can then experiment by inserting your male lucar into those slots to find permanent lives, ignition lives, lights on lives etc.
Be aware though that you won't (easily) be able to decide whether the one you wish to use is fused, and if it is, you might need to review which fuse and whether to "upgrade" it's rating. You could do this by getting a reading on your meter and then pulling fuses, one at a time whilst monitoring your meter
I have two "feeds" using those connectors from my relay panel. Oh, and at many motor factor shops you can buy special fuses with a "break out" lead fitted. They are usually found on those rotating display things with all the other useful bits n bobs. E D I T = here is a pic of one =
