Steve,
Assuming that Aux 1 is for your pool light and is powered by your GFCI outlet in the lower right of your ET, then do this...
Edit... I am not sure that your outlet is a GFCI outlet or that it is wired correctly.. Do this first... Turn on your pool light. Push the test on the GFCI outlet and make sure the pool light goes out. If the light does not go out, or the outlet is not GFCI.. do not go any further before we fix this...
Add a jumper from Aux 1 line in (existing light power..) to Aux 2 line in..
The cable from the landscape box should have a ground, neutral, and hot lead...
Wire the hot lead to Aux 2 load
Wire the Neutral the GFCI outlet neutral
Wire the Ground to the ground bus.
Turing on Aux 2 should power your landscape lights...
Thanks,
Jim R.