.. Where is it, and how do I get in?

After you get into your hotel room, Ewan, your Cathedral contact, calls to say that he'll be in touch later. You won't be able to get into the Cathedral hub until he calls you the second time.

That will happen after you find Moira --

How do I find Moira?

-- go to the safe house she told you about --

Loch Lomond

-- and operate the television in the safe house.

In the cabin, what do I do with the TV?

And when he does finally call, he gives you (sigh) yet another puzzle, this one to get the keycard to the Cathedral hub.

How do I open the safe in my room?

Once you have that keycard, go to the elevator and zoom in on the control panel. Put the keycard in the slot in the bottom, then push the large button that just popped out.

How do I get in when Ewan changes the code?