1. Put the bicycle into 4th gear.
2. Locate the two small yellow boxes on the left hand side of the rear hub.
3. Locate the adjustment knob under the right hand brake lever.
4. Rotate the adjustment knob under the right hand brake lever until the two yellow boxes on the left side of the rear hub are aligned.
5. Check the alignment after every 100kms or so.
Belt Tension Adjustment
To adjust the belt tension you will need a 6mm allen key.
1. Find the hole in the bottom bracket below the left hand crank where the allen bolt is that holds the rotation of the bottom bracket in place.
2. Loosen off this bolt (turn it anti clockwise) with a 6mm allen key.
3. When it is reasonably loose tap the end of the allen key gently with a hammer so that the two angled brackets inside are freed up.
4. Rotate the bottom bracket. This may take a bit of force. Loosen the allen key some more if it is too difficult. Ideally use the left pedal crank as a lever and the allen key as a pivot arm to push against. Rotate the crank against the allen key so as to rotate the bottom bracket and tighten up the belt. Don't over tighten the belt. It should be tight enough that you can only deflect it 5-10mm with a gentle push with your finger in the middle section of the belt.
5. Re-tighten the allen bolt in the bottom bracket and you are good to go!