First Timer - Storage Question

Hey! I’m setting up my first home server, I am trying to use a lot of things I already had at home. I am using an old thinkpad and have got the docking station and drives for a Raid 1 set up. I ordered some 1 TB drives on eBay. very small I know, but I have a good little collection that’s been taking up fairly little space and I won’t be downloading any large files anytime soon. I’m having trouble figuring out the order of operations here, I’ve got Ubuntu set up to the point of selecting storage. But now: Do I organize the raid system in my main pc, then plug it into the thinkpad? Or do I plug it straight into the think-pad and there’ll be a way to set up raid afterwards? TIA :)