Dell switches have the sfps ports set as the stack ports by default (you should be able to see this in the default running configuration). There is no option in the GUI template for this, which is true of the SR22xx and SR23xx switches as well. We have to set this on the CLI for the SR22xx and SR23xx switches, where as it comes already configured by default with the Dell switches.
I can send you a guide for setting up the SR22xx and SR23xx switches in a stack, but some of the steps (like the CLI bit I mentioned before to set the stack port) wouldn't apply. Dell might have better documentation available for you.