1. remove the rubber insert from your stirrup. 2. insert battery (V23a) (watch for + and -) and test LED (on/off) 3. insert LED - lower part into your stirrup. 4. insert treadplate from above. INFO: There are three slants on the center bar. The straight side must point to the battery compartment. 5. M4 screws (included in delivery) with a suitable Allen key (size 2.5mm). Caution: Do not tighten too much to avoid tearing off the material. Done. Have fun riding safely.