Part 1
A motivation interview with an HR person where they ask you loads of scripted questions and you give as much or as little detail as you feel, but the HR person can't deviate from the script so you have to judge it yourself.
Part 2
A knowledge test where you answer some multi-choice questions based on the booklet they provided you a link to for Stage 2. Remember things like a/c types and NATS airports, codes etc. but also be prepared to do some simple maths re. headings, airspeeds and flight times etc. No rush on this as there's more than enough time to complete, unlike the Stage 1 tests.
Part 3
The infamous and dreaded computer tests. Using an old BBC type monitor and a task specific keyboard (which has similarities with the keyboards used in Area Control Centres) with abcde buttons for each hand, a numberpad and some selection buttons. You have a few different tasks, all simple in theory but made complex by the high workload and quick speed required. Things like making moving numbers avoid each other by selecting one to 'destroy', categorising objects and numbers depending on a set of rules, but these rules can change mid game so be observant. Also, they might ask you to do this with one hand whilst at the same time answering maths questions with the other (sadly you only have one brain to use and very limited time)
Wait, I thought it was only Motivational paper, meeting with atcos spatial reasoning and numerical reasoning at stage 1?