UberPilots summary is very good.
As said, the process is very thorough and rightly so. The biggest failure point is the Command Assessment Sim / Interview but these are usually conducted fairly and they are not out to trick you but rather check you’re at the standard they want to see.
Of course, everyone can have a bad day so you get a couple of goes at the process.
I’d just add though that you should join EJ because you want to work for EJ rather than just using it as somewhere to get a quick command.
easyJet is very focused on promoting the right people with the right attitude and mindset. Don’t expect to see them filling the LHS as quick as possible with anyone they can or just because their number comes up. A place has to be earnt and that will involve hard work, but it is worth it.
Good luck. It’s a good place to be.