I met with AT&T at the career fair briefly and gave them my resume. I was told to apply online as well.
A few weeks later I received an email to do a brief Skype interview with the recruiter I met. During the interview she told me about the program and asked me behavioral type questions. A month or two later I received another email to interview with the hiring manager of the program. She told me about specific jobs, and we discussed which ones I'd be interested in and why I would like them. She also asked me about my co-op experience and personal interests. Two weeks later I received an offer. The whole process took about 5 months.