When you remove the front tumbler support, you'll see, as you lift the edge of the felt seal, tabs that keep it in place. You need to be very gentle as you bend the tabs to remove the old seal. They are very thin and can easily break.

Also, pay close attention to the direction the felt wraps around the support. If you wrap it in the opposite direction, the rotation of the tumbler will rip it loose, and can cause more trouble than just a torn seal: it has potential to stall the motor and burn it out.