How do I replace a drive belt on a Honda Harmony HRR216SDA?

Honda Harmony ll HRR216SDA drive belt broke. I've got a new belt but can't figure out how to get the belt on the pulley closest to the left wheel. Can't go from the bottom and the top has some sort of tensioning bolt that's in the way.

I would also like to replace the bottom rear guard that flaps. It is connected with a long pin with some kind of nut on the left end. How does this come apart so I can slide the new rear guard on?