A bridge locating fixture is handy for locating bridges, set it to the scale length, the fixture has a saddle in it which fits into the slot on the bridge. When you have your bridge positioned drill a hole through the bridge and top at each end of the bridge saddle slot to receive a brad to use in locating the bridge while glueing. CAUTION do not drill through a fan brace. Bridges tend to slip when glueing. I recommend that you do something to avoid this. In the beginningI held the bridge for a half hour with my hand inside the guitar and the other hand pushing on the bridge-SILLY.