Power off the PS4 completely
Unplug the power cable and all other cables
Remove the hard drive cover if needed
Remove the warranty sticker if present
Use the correct screwdriver for the model
Remove the visible screws on the outer shell
Release the plastic clips carefully with a plastic pry tool
Lift the top cover or shell slowly
Disconnect any internal cables only if necessary
Keep track of all screws and parts
Avoid forcing any piece open