I found the screen on Main for initially setting up my array with 2 drives a few days ago and set up the array with a single parity and single data disk.

 

In the manual it says, to add a drive:

 

5. Assign the new storage device(s) to a disk slot(s) using the Unraid webGui.

 

But when I go back to the screen that let me add drives, it shows me the 2 drives I added already, and not the rest of the slots.

 

I've tried spinnig down the array to see if that would give me the list so I can add new drives.

 

I did pre-clear the 2 new drives and they do show up in the unassigned devices list. (On the same page above, under boot disk)

 

And it must be easy to find this GUI for adding a new drive, since I can't find any topics in the forum about how to add a new drive, so obviously millions of other people figured it out! But I've tried several times over the last couple days and I have failed to find it, so I'm asking the newbie question here.

5 minutes ago, madmanpierre said:

But when I go back to the screen that let me add drives, it shows me the 2 drives I added already, and not the rest of the slots.

Array must be stopped, if you still don't see extra slots set the number of slots to more than 3.

Thanks JorgeB, just found that and came to reply to mine. I guess I'm going to have to read and understand the difference between spinning down and stopping.