Would like to add internal SSDs to new ON install and general guidance

Current version 6.2.0
OS: Debian 11
Hardware: 6th gen i5, 32GB RAM
Storage: 1TB SSD, 2TB SSD, 4TB SSD

Currently I have about 12 different servers running on 6 different machines and would like to consolidate everything to one machine using ON. So far I have setup the installation via the official docs. Sunstone works fine and everything shows up as it should.

ON is installed on a 1TB SSD. I have two additional drives I would like to install to that are mounted at /mnt/disk2 for the 2 TB, and /mnt/disk4 for the 4 TB. I am new to ON and cloud management in general. The 1 TB SSD that ON is installed on I would like to install several small docker containers like home assistant, jitsi meet, webtop etc, the 2 TB will also be for docker containers for peertube and funkwhale, and the 4 TB will be for VMs that run things like mastodon, matrix, and other federated services.

The only disk I see within Sunstone is the 1 TB that ON is installed on. What would be my next steps as far as using the other disks/making them visible, and would they be designated at file, image, system? Do I need to create a new cluster? This is what confuses me as I do not currently understand the lingo. Thanks in advance for any help you can offer.