put the new belt in, and then the bottom timing cover on followed by the pulley. turn that to zero and then line up the cam gears. slip the new belt on, make sure its really tight on the non tensioning side, other wise that defeat the purpose of the tensioner.
once it's lined up, release the tensioner,
turn the crank clock wise, this will cause the tensioner to tighten up a bit. while adding some pressure, tighten the tensioner down, and your done.