It's pretty easy.
1. unload rifle and so forth
2. remove bolt.
3. rotate the cocking piece counter clockwise (as viewed from the rear)
4. the bolt head and guide deal should now come forward and off
5. use the forked part of the guide deal to unscrew the firing pin from the cocking piece. It's under spring tension, so be careful not to let them squirt different directions.
To reassemble:
1. screw firing pin into cocking piece, through the bolt body, until the pin is about flush with the rear of the cocking piece.
2. slide the bolt head over the forward part of the guide deal, then rotate the bolt head 90 degrees (only one way to do this, so relax)
3. with the cocking piece forward, slide the guide deal over the firing pin in front while putting the forked part over the "T" protrusion on the cocking piece. When the guide deal goes into place, the notch on the bolt head should go into a recess on the forward edge of the bolt body. You may have to rotate the bolt head a little for things to go into place, but no big deal.
4. will everything in place, rotate and retract the cocking piece into its rearward position.
Not too bad.