Freightdoggie,
1st stage involves colonic irrigation, full rectal examination and a sense of humour test javascript
:smilie('
')
wink
No seriously, first stage of the Wings ATP scheme is the application form. Stage 2 which it looks like you've been invited to involves a maths test, a general aviation knowledge test and a couple of group discussions.
Nothing too taxing but it pays to be prepared and make sure you're brain's awake on the day.
Good luck. They're a good bunch! If you have far to travel might be worth getting a room at the Manor the night before.
All the best!
The 'Fro