Attach floats to the raft by attaching them to the underside of the cross supports near the outside edge. If you are using big logs as floats, attach one to each side of the raft. You can also use 55 gallon drums, marine foam, tire inner tubes and anything else that is buoyant. If you are using logs, you can nail them on to the cross support. If you are using hollow floats, however, you will need to attach them with rope, marine webbing or steel cable.