I couldn't find any info on the internet when I was looking. KittyKosmo is the first person I've seen that also has one. I'll try to post some pics just to prove the sail exists
There is a 'cup' or 'socket' molded into the front seat to accept the mast. If you don't have one you might be able to mount it some other way. There are two cross braces than bolt to the sides and the mast passes vertically through these into the socket. Also, the outriggers have brackets that bolt to the ends of the cross braces.
I sailed it this week and it was a blast!- after I remembered you have to sit with your back to one side to steer with the rudder (the rudder is just one oar)
Hope these pictures come through.