As shown already the 350D has two tool-free 5.25in drive bays for easy drive installation. And, as explained, it has a bunch of HDD/SSD cages as well. Let's look at 3.5" storage units though.
The 350D comes standard with one 3.5" HDD cage which supports two 3.5 inch or 2.5 inch drives in any combination. Here's how you install the actual HDD.
You can easily insert and/or remove these. You place the HDD in a tray, slide it backwards in the cage and secure it with the hinge. It is as simple as that. The HDD hangs in rubber inserts. One such tray can be used for an SSD as well, these are secured with four screws at the bottom side of the tray. But again let me mention that there is a cage especially for 2.5" devices.
Right, we are moving back to the front-side again as there is some bezel stuff going on we have not told you about just yet. Have a peek at the lower aluminum bezel insert.
The front side panel is actually brushed aluminum, if you push on two buttons you can pull it forward you can take it out. You'll then notice removable and washable dust filter for intake fans.