Just finished with a shower remodel, I was going to install the shower arm, but since it's behind the tile now I thought I would ask first. My plumber did the last one but for $150.00 I thought I might be able to pull this off. He put some pipe dope on the threads and then wrapped 3 times with white pipe tape and hand twisted it on. Is that really it? I guess my fear is leaking behind the wall but I can't see back there? Any suggestions?

thanks!