Welcome from Utah!
All drivers backrests go on the same way. After pulling your seat off and installing the mount (one time installation) you simply insert the backrest. Note that the grasshopper has no adjustment so you may want to look into the OEM backrest or Utopia backrests. You can also use the OEM mount with a Mustang backrest if you want to save a few bucks.
Retired USAF, IYAAYAS!
2008 V-Star 1100 Custom Bobber project
2011 Crimson XR with Forged Highway Bars / Hard Bags / Passenger Backrest, Ness parts including Smooth Layback Plate Frame/Mount / Rad 3 Mirror / deep cut grips / drivers floorboards /shifter peg / brake peg / passenger pegs. Witchdoctor black rack, Lloydz filter / timing wheel / VFC III, 7Jurock windshield, Drag Specialties seat.