Researched the net found info on checking the rec/reg and the 3 yellows or the alternator.
Didn't want to nacker the new battery so:
Put the old battery on charge (low charge rate) next morning, put it in started fine, done a few more miles on it, later that evening, would not start on the key hummm.
Got a multi meter ready to check after work today.
Charged the old battery for a few hours 12.97 with the multi meter set to DCV 20, bridged the battery bike running at 5000 rpm as the info I had said got 12.71 alternator problem maybe via the info I had?
On to those 3 yellows, well never used a multi meter before for ohms so may have set it wrong (tip here would be good) all I got was a 1 on the far left of the screen on all of them, tried it on the different settings ignition on and off????? don't know what I was doing but don't think I did the test right, a-b, b-c, a-c???
Anyway, before I get other jobs done I want to get this sorted so could someone please give me a bit of help?
Here are some pic's

The multi meter I'm (trying) to use

Alternator wires disconnected, I tested the ones on the left that went through the V the others came out the loom (am I right?)

Found this where I guess a block normally is, one browny-burnty again.

Reg/rec the connection bottom row right is browny-burnty looking, can I test the reg/rec?
Basically don't want to ruin a new battery, what can I do to fix whatever may be a problem? I've tried a load of searches to found out myself but just cant work it out

help