Per diem & MALT calculations?

After finding out that our last move will be covered once my husband separates from the Navy, I was wondering how the funding is calculated? We will be traveling a roughly 24 hours, 1,375 miles and it will be my husband, our son who is 1 year old, and myself. Sorry to bother, I'm just trying to figure out the financials of this final trip home. Also, is this an upfront pay or will it be paid after the trip? I'm pretty clueless to this as you can see. Thanks in advance