Here we have the right drive bay. The HDD is secured with two plastic retention clips. Let me show you that.

Simply push on the two clips, slide the HDD into the drive-back, and once you hear "pop" you can stop as it's secure. Within a second you can pull it out if you want to.

The plastic slips have little rubber mounts on the inside, preventing noise / resonation as well.

This is how the liquid cooling block is protected from damage during transport. At the block-side a little foam is protecting it, and the block itself is secure with the help of some extended screws with springs.