What happens after a job offer is made.

So i just got the word that i will start processing in may1st,my supervisor told me she would be sending the offer online and all i had to do was accept it. My question is when does the background happen,before or after they make the job offer. That is going to be my final step before i actually head out and i know it takes a few days to come back which is good because i need to pack, i just cant remember if they do it before you get hired or after(i only remember the physical stuff that you have to go to ohio for) any help would be greatly appreciated.

After the job offer is made, you go on jobnet to accept it then authorize them to do your backgorund check. Could take 2 weeks-2 months for it to come back. Then you pront off your paperwork for HR, see what you need to bring, then process in. I'm processing in May 1st too, early in the morning.