I posted this on another thread...
You will get a packet in the mail and then have 30 days to choose your school and send in your acceptance. As you'll see, there are some disadvantages to being given the scholarship on the 1st board because numerous recipients are going to have to choose their ROTC school before they are officially accepted to the school. Then when they aren't accepted down the road, they will have to contact Cadet Command to get their school choice changed. It probably works out just fine 95% of the time but every year, you read about the process not working out for somebody.
The other thing you have to deal with (which will all be explained in the packet you receive) is the DoDMERB health screening process. You will read about numerous kids having issues with past medical problems that will hold up the process. Most of the time, they just need to see the medical records to verify the the issue is no longer a problem. For example, my son broke both ankles in high school so we have to show that he was fully recovered and cleared to participate in all activities. Some issues will be more serious and you may actually need a medical waiver before you can be part of ROTC. My daughter went through that and actually had her scholarship pulled in April. We had to apply for the waiver and go to Plan B while we waited...and waited...and waited. Luckily for us, she heard back in June that her waiver had been approved. Her boyfriend had to wait OVER A YEAR for his waiver to be approved by the Air Force so he ended up paying for his Freshman year of college on his own and NO, there is no reimbursement for that.