[Doncrise]

I have a empty double gang box on my patio with 12/2 running to it. I have power to that point.
I have PVC pipe running under ground approx 30 ft away which has 12/2 run through it.
What I'd like to do is put a outlet and switch in that double gang box. Receptacle first and then switch that would tie into that underground ran wire where a gfi would be.
Ideal is to have an outlet on patio and a switch that would control a fountain pump which would be plugged into a gfi.
How do I do this? I basically need to know how to wire a powered 12/2 wire into a receptacle then a switch into a gfi. Thank you

[ebaines]

It would make sense to have the outlet in the double gang box be a GFI version, and then power the switch and fountain pump from the load side of the GFI so that everything outside is properly protected in case of ground faults anywhere.

[hfcarson]

be aware if the 12/2 in the underground conduit you are referring to is Romex, you should consider replacing it. Romex is not permitted in wet locations like underground conduits.
It may last a long time but it is not appropriate...