1 - First of all, if you have not done it yet, in the Admin platform make sure to attach each lock to the right bike. If you have many locks you can use the search bar, place on top of filters (not shown below).
2 - Secondly, make sure each bikes' rentable attribute is enabled and assigned to the right Hub when you roll them on the street. To assign bike you have to use the 'Move to' action, see picture below.
3 - Lastly, when you physically place the bikes at their destined hub locations, go on the Donkey Owner App, and 'Relocate' each bike. This will allow the system register the exact location of the bike.