The Meshify 3 comes with 2 pre-installed brackets supporting either 2.5" or 3.5" drives. Each bracket can support either 2x 2.5" SSDs, or 1x 3.5" HDD.
The brackets are 2-parted, and screws in to the side of the drive:
These have multiple mounting points for you to move around on the back of the motherboard plate to suit your build:
