1) Unlock and remove the bike's seat 2) Pull out the tool box (if your RT still has one) You should be looking down at the battery at this point. 3) Remove the side covers by un-tensioning the rubber bands that cross over or around the battery and set them aside 4) Unscrew the knurled knobs of the battery hold-down frame and pull it away Now you've removed (most of) the things in the way. It's still a tight fit and your bike may have a wire bundle running over the left side of the battery that will make things difficult 5) Unscrew the pos and neg leads on the top of the battery and bundle them so you don't forget which wires go with which lead 6) pull out the battery
To put a new battery in, reverse all the above.