I am confused Ken.
If you were able to take that photo, you already have access to the outside shower.
And the spigot for the shower faucet is sitting below & in the middle if the hot cold controls.
You simply mount the existing hose with some thread seal.
If that is an old photo & the door is locked & your don't have the key, you simply lie on your back & with a flashlight & a screwdriver & push the flat blade arm of the lock to an open position.
If i have misread your question, I apologize.