First we need to turn the device around.

Unscrew the thumbscrew on the back using a Torx 15 bit or a flathead screwdriver

Slide the top off as shown

The fan can be removed by rotating it up and out as shown

Once the fan is out of the way unplug the fan

The RAM shrowd can be moved out of the way to give access to the RAM

Press down and out on the installed RAM to unclip it then pull it out

Remove both marked screws with a Phillips #1

Unclip both WIFI antenna

From there they can both be removed

There is a small amount of adhesive on the SSD cover. It can be peeled off to release the SSD

Remove the three marked screws with a Torx 15 bit

Once unscrewed the heatsink can be lifted up and towards you at a diagonal

The CPU can now be removed by pressing down on the lever, pulling it away from the CPU, and letting it come up to release the CPU latch.

First unplug the front speaker and IR receiver.

Then using a Torx 15 remove the marked screws

To remove the motherboard I would recommend watching the video

Congratulations you have successfully disassembled your HP desktop.