The thing on the spoke is a magnet, hold in place by a small screw. The center of this magnet should be aligned with a line engraved on the fork attachment. Most importantly, the spacing between the magnet and the attachment must be very narrow, like 1-2 millimeters. The following 3 steps installation guide is for a Vetta C-500 but your Ascent should follow the usual way to fix them.

STEP 1
Clamp the bracket around the handlebars and tighten in place. All Vetta cycle
computer brackets are designed to work with 26.0 - 26.4mm standard
diameter road handlebars. Shims are provide to fit smaller 25.4mm mountain
and road bars. Make sure not to over tighten the bracket as this may result in
breakage. The bracket only needs to be tightened enough to keep it from
spinning on the handlebar during normal riding.
STEP 2
Loosely, mount the C-500 transmitter to the leading edge of your left fork
blade using the flat rubber block and the 2 zip-ties provided. The arrow
printed on the side of the transmitter should be facing the spokes and pointing
toward the bracket on the handlebars.

STEP 3
Attach the spoke magnet to the wheel, and adjust the alignment of the magnet
and transmitter so that the magnet passes the transmitter within 1-2mm of
the small line molded into the lower part of the transmitter and the word
MAGNET printed on the side of the transmitter.