EAM
Here is the link to BA Careers website with all the requirements.
Start at DEP recruitment then work through assesment etc.
BA Recruitment
One point I feel I must make is how come you didn't look here yourself? There are going to be some tough days ahead if you want to fly "the BA Way" so get cracking on your research. Try the search function here at Pprune and how about Google?
PS I have dropped a key phrase into this post for you to quote at an appropriate time - can you spot it?