Looking at your picture take the bolt out of the right hand side underneath the corner at the PTO. The bolt and jam nut then screw in the end of the shaft there on the same corner out the back. Next push the shaft in until the detent in the shaft lines up where the bolt threaded in orginally. This may take a little while to get the shifting forks and gears to line up so it will go into 1000 rpm. After that put the bolt back in where it was and thread it in and finish tighten with jam nut.