Best advise to repair leaky garage roof

I have water coming in the roof with the source to be determined shortly. I would like to repiar the area (mainly the ridge) of shingles that are missing tabs, but how can I do this without ruining other shingles around them?

I have a claims person coming out within the next week and I may need to put a large tarp over the roof....how would you suggest doing this so I do not damage anything else on the roof?

Is there any good way to begin locating the source of the leak without removing shingles right away or should i not mess with it until the claims rep comes out?

 

Don't mess with it until the claims person comes out. Tarp it, surely, as it is your obligation to mitigate loss. I would stretch the tarp over the area and use button cap nails to fasten it through the grommets to the roof. The holes you create can be sealed from underneath the shingle tab.