Do you have a question about the Genesis Titan 800 and is the answer not in the manual?
Install fans or 5.25" ODD devices after removing the front panel and unscrewing the side panel.
Place SSDs in designated areas and secure them with screws after removing the side cover.
Install HDDs in designated areas using supporting screws on both sides within the HDD tray.
Connect front panel I/O connectors to the motherboard according to the motherboard manual.