https://www.gamecrate.com/how-to-turn-an-old-pc-into-nascan you elaborate more pls
Other than that, tons of you tube videos available.
Since you are a graphic designer, you need large file handling capabilities; with poor internet and expensive cloud services, it is a bit of a difficult and time-consuming task. So the best is using NAS for backups and storing your contents. I've mentioned the cloud because of the availability; you can access those anywhere, anytime, as your convenience.