Synology DS720+ Hardware Installation Manual page 14

5 If needed, repeat the steps above to install a second SSD module into the second slot.
6 Reconnect the cables removed in step 1, then press the power button to turn on your Synology NAS.
To remove the M.2 NVMe SSD module
1 Shut down your Synology NAS. Disconnect all cables from your Synology NAS to prevent possible damage.
2 Push the lever outward. The module will pop up and be released from the slot.
3 Hold the SSD module and remove it from the slot. Replace the covers.
4 Reconnect the cables removed in step 1, then press the power button to turn on your Synology NAS.
14 Chapter 2: Hardware Setup