How? You get your tools out, unbolt it, and stick that bad boy back in there.
Seriously though, the brake pedal looks intimidating doesn't it. All the bolts and linkages. But it's not as bad as it looks.
Some suggestions:
1. get a factory service manual, it has great pictures of how the parts fit together
2. look online for a parts diagram, any Yamaha dealer will have them on their site
3. take lots of good clear photos of the pedal and all it's parts, different angles, then just take it apart and keep your parts organized, look at the photos and reassemble, just take your time