First connect to HR by applying online for opening post or recommendation, HR will interview you on the phone, this interview is mostly for connecting your basic information and HR will find you the team to interview with. So it is important to make clear and identify yourself of what you are targeting.
Once you get contact with team, usually they will give you a phone interview first with 45 min one round and they will give feedback to HR. If that is getting through, the next step usually will be on site.
HR will help team arrange the onsite interview, you will meat the team member, 3-5 person in a day. I don't see SAP pay any travel or accomodation. I don't think it is very tough, it usually depends on person.
You probably will meet manager as well in this onsite interview.
After that, you can wait for HR's notification of getting offer or not.