Okay. I just bought a new laser and need help learning how to use it. The first laser I owned was just a basic model that had to be level to function. We had to shoot points and run string lines to create slope. The new laser has a manual overide button so I can tilt the laser and shoot slope into a patio etc. Can somebody give me the steps you would take to set up a pad for a 20 ft. x 20 ft. patio with a 1 to 10 slope?