Ikea Vika Amon / Ikea Alex Mounting

Hello dear ones,

I want to go to Ikea on Saturday and buy myself a new desk:
I was thinking of the Vika Amon tabletop (black-brown), Vika Alex storage and drawer unit in white.

Now my questions:
How do I attach the two Alex units to the tabletop?
And I wanted to put my computer in the Vika Alex storage - do you think it will get too warm for the computer?

Best regards

I would never put a computer in a closed piece of furniture, I also have the Vika Amon tabletop, with the computer underneath on an EDNET mobile computer holder on wheels.