I have just done a good calk jobs.
I cut the applicator end just the width you want the caulk to be, and at slight angle(15-20 degrees). Hold the gun perpendicular to your work while in contact with both pieces, lean the gun slightly towards the direction you want to run the bead. Squeeze the caulk out at a slow steady pace while watching the outside endges of the applicator and adjust material and speed accordingly. If you mess up keep the nozzle in the bead and just back up, the applicator sets the depth and angle. Give it hell.