Unraid Upgrade

I'm looking for some advice on the correct procedure to upgrade my Unraid setup.

My current setup is a GMKtec NucBox G3 and two external 6TB hard drives. One hard drive is used as the parity drive of course. I mostly use Unraid as a media server and hosting a website or two. The setup works great and barely sips any power. I am running out of storage so I bought a 10TB hard drive and a 4 bay hard drive dock, and I thought I would upgrade the RAM while I am at it so I got some Crucial DDR5 16GB RAM as well.

I also have a 500GB SSD lying around which I might use to replace the existing SSD that I am using for my cache drive (doubling the cache pool), but I am not sure I can do that now as well. All my appdata files are on the cache disk (and backed up to cloud storage). I only have one 2280 slot.

I would of course have to use the new 10TB hard drive as the new parity drive and move the old 6TB parity drive to become part of the array. And all of the hard drives will have to be mounted in the dock. I know the external USB storage thing isn't great for Unraid but it's what I have at the moment and has been working very well for a while. In a couple of years with some saving up I'll build a proper Unraid machine.

So, can anyone please advise me on the correct procedure to for this upgrade? I have read the documents on this but I am not sure the it still applies with exactly what I am doing, and I'd rather ask here and make sure.

Thanks in advance for any advice and guidance!