Depends on the wheel and if it is a double drive or a single drive.
With a double drive, the drive band goes around the drive wheel, around the flyer whorl, back around the drive wheel and around the bobbin whorl. You increase the tension on the bobbin by moving the Mother-Of-All back.
With a single drive (scotch tension), the drive band goes around the drive wheel then around the flyer whorl. there is a separate band that goes around the flyer bobbin and you increase tension on that band to slow down the flyer.
If you can post a picture of your M-O-A, I could help more.