How to fit Fabric in your Really Tough Tuffie
Unscrew the outer nuts and bolts and lift the top section off the whole bed.
You will see the 12 plastic nuts and bolts that hold the fabric in place. You undo all those with your fingers.
You can now just lift the sheet off.
Use the old sheet to mark where to put the holes in your new sheet. Burning the holes is great (for example with a soldering iron), but cutting them as small as possible is also good.
While you have the top section off it is also a good opportunity to give it a good clean inside.
Use the same plastic nuts and bolts and fix the sheet over the stuffing. Replace the top section and screw it on with the metal nuts and bolts.