"Process" is a menu. Assuming your project already has measure boundaries where you want them. Let's say you have chopped your clip where it sounds like a measure boundary. So your left-side clip starts at the right measure, but ends too soon or too late in the project. Select that clip, and click on the "Process" menu and select "Fit to Time". Make sure Format is M.B.T. Choose the Event Times option, make sure stretch audio is checked, and enter the new time for the end of the clip. Make it be the measure where the clip should end. "OK". Now it should line up pretty well unless the tempo was crazy changing during that clip. Then slide the right-side clip to begin at that same measure, where it should start, and choose another chop point and repeat the process.