OK, I have an Oyster card, which I have set up "auto top up" on. I need to activate this at a specific station, I have chosen Paddington.

To make my life really simple, TfL list no less than two Paddingtons:

(H&C line) & [National Rail] station

-and-

C&D & Bakerloo lines.

I have chosen the former.

Now, I am not tremendously familiar with Paddington, so can someone describe where these gates are?

I will be arriving on a First Great Western train into Paddington (from Penzance). I tend to leave the platform (Typically the ones towards McDonalds), and carry on straight towards all the shops and left a bit to access the underground (if that makes sense)? Which lines/ticket barriers are down there? (I take the tube to Liverpool Street to change for the Central Line, if that helps).

Now should I use my Oyster card to exit the "normal" platforms, and then again down in the tube barriers, or just the latter? Bearing in mind I have to "activate" my card at the "correct" barriers.

Help!

A very confused L_U.

H&C & National Rail are the above ground section of Paddington, C&D & Bakerloo are the underground part of the Underground. If you follow me.
The latter have ticket machines/windows downstairs - towards the centre of the station, under the glass food bit.
I'm not sure where you'd have to go for the overground bit, but the platforms are to the left of the station, IIRC. Used to get the Tube into Gt. Portland Street every morning for about a year from there, odd that I can't really remember much more!

All I remember is I walk "down" some stairs, but end up on a tube platform that's actually in the open air.

I know it sometimes involves changing trains at Edgware road. Any idea?

Ah, I think I know!

Does the H&C involve going over a footbridge from the "normal" platforms (opposite end to the shops)? Whereas C&D involve going downstairs (towards the shops)?

Yes, I believe it does.

Ah, I think I've chosen the wrong bloody barriers to "activate" on, but it's no tragedy, just means I'll go the opposite way to normal.

When leaving London, I normally arrive at Paddington via the H&C line and end up on the footbridge (looking down on Heathrow Express).

However, when I get to Paddington from National Rail I walk towards McDonalds etc and go down some stairs, and that must be C&D?

Sounds right to me.

Ah, good.

That explains then, why when arriving at Paddington I always end up changing at Edgware Road, but when going back to Paddington I can get a train straight though; It must be because I end up on the Circle/District line when leaving Paddington, and somehow the H&C when going back (and thus, end up arriving at the opposite end of the station to how I left).

That's H&C then.

Paddington Map

With photos so you can know when to expect luggage trolleys.