How do I install the OPC belt cartridge in the HL-3450CN?

Open the front cover and release both belt cartridge lock levers by pulling them up. Remove the orange belt tension release pins from both sides of the OPC belt cartridge and remove the protective sheet, then insert the OPC belt cartridge into the printer guides with the flat side facing you. Be careful not to touch the green surface of the OPC belt or expose it to light for any length of time, then lock the belt cartridge lock levers and close the top cover. (Page 1)