[Bob Broberg SPF667 460BB]

John, you mean the submarine belts? They must be secure. Probably through a frame/support bar or large steel plate beneath the floor. Don't drill the carpet, cut it. The prime reason for the belt is to keep the waist belt low on the hips. Should not be difficult install. Use good size, quality, grade 8 or better bolt, perhaps 5/8 inch.

Hope this helps

AZ Bob