OK - A brief overview as I agree - when you first visit the site it can be a little daunting.
First, goto:
www.ais.org.uk(Make sure you get the .uk bit or you will be confused.)
Now, Login. If you haven't already registered, register first - it's free and that part ain't too complicated.
(Why they need a login is beyond me as they do nothing to validate the individual and never send out mailings so it seems a totally unnecessary step.)
Once logged in you will be taken to a screen welcoming you by name in the top right hand corner. Now, click the 'Publications' tab at the top of the screen and the UK AIP option that appears in the drop down list.
Again, in a piece of web design that leaves you bewildered this takes you to a screen with a text link to 'The UK AIP package'. (That's it - a link to the page you just selected!) Click this link.
On the scren that follows, click the following link to the specific aerodrome details.

Now, you get a list of UK aerodromes and the necessary charts. My recommendation is that you begin with a smaller local aerodrome that you know reasonably well. This gives you a huge boost when trying to understand the charts for the first time. If you pick something like EGLL the number of charts is immense (35) and this can make trying to plan your first flight with charts seriously daunting.
I hope this helps a few folks pick their way through the site. When you get to know the site better you will quickly see how to link out to other national sites providing similar information for aerodromes in other countries.