Then you should extract the mainboard mounting plate. It is fastened with screws at the back panel. Pull at the loop to take it out.

You should have something like this as the result:

A bare chassis with a frame to mount the power supply. I’ll install it shortly. Let’s first take a look at the mainboard mounting plate:

This is a very delicate thing. The plate is molded from a thin sheet of aluminum and has low torsional stiffness. You have to handle it as gently as possible. A drawback, the exhaust fans are connected via Molex connectors:

I’m especially surprised that there are two separate connectors. The fans could easily share one connector, considering that they are anyway going to be connected in parallel. The problem of centering the mainboard on the poles is solved originally – one of the poles has a jut:

This helps avoid misaligning the mainboard during installation. I took a mATX mainboard from Intel and a Zalman CNPS8000 cooler.

Its dimensions match this barebone perfectly. There is enough space between it and the power supply for normal air intake.