I have a problem with my indicators and horn on my bike. Now i have a multi meter thats knocking around in the garage for ages, dont even know where its come from

, anyway, i havnt got a clue about electrics and how to even use it and dont know where to start.
When i got the bike, the indicators were very dim. After the first outing off road, they started to stay on constant instead of flashing, and still very dim. Now they dont work at all, and neither does the horn. Headlight and brake light work fine though.
I had a quick look at the wiring behind the headlight and all seems ok, if a little and damp after jet washing it a couple of days ago.
Anyone help me out on this please and point me in the right direction on where to start.
Cheers.