First of all be very carefull if you decide to go on the roof we would advise calling a local reputable roofing contractor to assess the roof leak. If you insist and can locate the area try and secure a tarp over the roof leak area and either tie or and some weight to the tarp to prevent the tarp blowing away.
After a while if you have the right area the roof leak should stop. If the leak persists action is needed underneath the leak in your home. Tie some string to a screwdriver or long nail and push through and make small hole in the ceiling of drywall ( this is easy to repair later) the roof leak water should come out down the nai and string and you can catch the water in a bucket at the bottom this will save the ceiling falling in until you can get a qualified roofing company to look and repair the roof.