Hi, you need to adjust the settings for the tyre circumference and for the number of pick-up magnets you used, the manual describes how to do this.

These speedo clock kit comes with everything needed to fit them, but they still need to be manually wired and connected into your moped wiring loom.
Unfortunately speedo clocks kits don't have adaptor plugs where you can simply unplug a standard speedo and plug in the aftermarket one.