Install the 3.0 volt, CR2032 battery. Unscrew the battery cover on the back of the unit using a coin. Insert the battery with the positive pole, indicated by a (+), facing outward. Replace the battery cover.
Attach the magnetic transmitter to a spoke on the front wheel of the bike. Ensure that the magnet is directed towards the outside of the wheel, where the sensor will later be mounted. Tighten the transmitter with the thumb screw.
Loosely mount the sensor unit to the right leg of the fork using two zip ties, positioning the sensor so that it faces inward, towards the transmitter. Adjust the position of the sensor so that when the wheel spins, the transmitter passes within 5mm of the sensor. Reposition the transmitter as well, if needed. Cinch the zip ties tight when the sensor and transmitter are properly aligned.
Peel the backing off of the tape on the back of the computer bracket. Fasten the bracket onto the handlebars in a location that will allow you conveniently to read and work with the F20 computer when it is mounted. Take the o-ring that best fits the diameter of your handlebars and attach it to the two plastic hooks on the top of the bracket. Bring the o-ring around the underside of the handlebars and attach it to the hooks on the bottom of the bracket.
Insert the F20 computer into the mounting bracket and lock it in by twisting clockwise.