Craftsman rider mower clutch stays depressed

From your brief description, I'd suggest the spring which deactivates the "clutch" is probably broken. There really isn't much of a clutch on riding lawn mowers. What happens is, the drive belt is allowed to slip on the main pulley coming off of the engine when the pedal is pressed. When the pedal is released, a tensioner pulley takes up the slack in the belt and friction is once again applied against the belt and things start to happen. If the clutch pedal is not returning to its normal position, this is usually a sign the return spring is no longer connected or is not functioning as it should be.

Secondarily, it might be that the drive belt is either dislocated or broken.

You'll have to get under the mower to see what is going on. This may involve dropping the mowing deck away from the chassis.

Here is an image of a Craftsman deck. Your's should look something very similar to this:

According to the Operator's Manual, page 16, under "Parking Brake" release the brake by depressing the pedal and then move the speed control lever out of the "park" position, into one of the speeds 1, 2, 3, 4, 5, or 6. That's it.