This took me a while to figure out so thought I'd post it on here if anyone else runs into this. Sorry if this was covered in another thread already.
By default ports 1/2 and 1/3 on the switch are set up for stacking. You can remove the stacking and use them as regular SFP ports if you want by entering the following commands.
(ArubaS3500-24-POE) #configure terminal
(ArubaS3500-24-POE) (config) #delete stacking interface stack 1/2
(ArubaS3500-24-POE) (config) #delete stacking interface stack 1/3
(ArubaS3500-24-POE) (config) #write mem Saving Configuration...
Configuration Saved.
Hope this helped you out.