Any advice accepted. Learning to work with ubuntu

Built a PC with spare parts from updating my gaming rig. I am looking to build a self hosting NAS/cloud storage. I put Ubuntu on it and am following guides to set it up properly with the right programs. I am more or less putzing around just to learn and get away from windows, google and the such. I know enough to set things up but not how to be sure things are secure and safe. If ya'll have any suggestions as to what programs work best for certain tasks or video guides that explain things well, I greatly appreciate it. Here's a link to the build: PCPartpicker I am currently following a guide to set up SSH to securely remote into it.