I used ABS, PLA should also work here, but you may want ABS for the sections close to the bed.
Print all three pieces. Install heat set inserts in the two smaller holes on the frame block, and in all 4 holes of the bed block. The bed block is designed to fit into the Zip tie slot on the stock bed plate. The Bed latch then screws down to hold that in place. The zip tie holds the bed end cable ends in place. You will need to disconnect the control box ends of the heated bed power cable and temperature sensor to be able to route the cable. I left a section of the existing stock cable jacket tube in place at the frame end for cleaner looking routing, you will want an inch or two to protrude into the cable chain at a least, and you could optionally leave the whole thing on if you like.