1) Step 1 : install alloy rear carrier onto your bike , Adjustable arms for adjusting the height of your rear carrier. Fits most hardtail bikes including fat bikes.
2) Step 2 : install alloy box holder onto the rear carrier .
3) Step 3 : install rod holders to the alloy box holder.
4) Step 4 : Attach the Optional Black box - fits exactly into the rear box holder. Can be removed and re-attached when required.