take off one of your hubs, drill a hole in your rotor guard, remove one bolt from the rear of the hub, insert the magnet in place of the bolt you just took out, hook up the cable to the hole in the rotor guard (almost like a throtle cable),route the cable to the handlebars or wherever you are mounting it, attach mounting hardware, clip computer in place
put the hub, rim and lug nuts back on and you are done
about 1 hour worth of work if its your first time and about 15 minutes if you have done it before.