As far as replacing the drive, which one is disk 1?
The one on the left labelled "1".
I assume I pull it out and put an identical brand size and model or will any 1 TB drive work?
Any disk that has the same specs (size, capacity, RPM and cache) would be fine.
Are there special jumpers or anything to set on it?
No, they are SATA disks, jumpers are only on the older (not used anymore) IDE disks.
Once I put it in I just go to the Drive through the interface and then go to mainternece click array 1 and rebuild?
Reboot, go to admin page, System -> Storage -> array1 -> Select the new disk -> Rebuild RAID.
Any suggestions on a replacement try for my model?
Any standard disk of the same size should be fine, make sure you have a backup (just incase) before going through it.