Unable to format disk

I just recently installed Rockstor for the second time, this time onto a different hard disk than the first time. I want to create a pool with the two other disks I have, one of them being the disk I installed Rockstor to the first time. When I go into disks, I see them both, the one I did the install to the first time has a cog wheel icon next to it, when I originally clicked on it, it gave an error message. I have since rebooted and now when I click on the cog wheel nothing happens. I can’t create a pool until I wipe this disk, how can I do that? I am not terrible good on the console, but if there is a command or two I need to type, I can do that.