There's a few videos online about it and a couple dealt specifically with cases such as yours here. If you google "how to remove bumblefoot on chickens" it will come up with a plethora of information.
We have only had one instance, both feet on a production red hen. Both had scabs and was caught fairly early.
Fairly basic steps: Clean, soak, removal, clean, dress, then every 24-48 hours remove the dressing, clean and redress for a week or so.