Currently bonuses are paid in either two or three installments, depending on your situation.
If you have a college kicker, then you receive 20% of the entire bonus (kicker added) while in NFAS.
I received mine a week into NFAS. $5,000 pre-tax out of $25k.
After NPS I will receive 33% of the remaining balance, then the rest is paid after NPTU.
If you are picked up for STA-21 and can finish NPTU, then you keep every dime.
If you have no college kicker, then you receive nothing while in NFAS or after it.
After NPS you will receive 33% of the remaining balance, then the rest is paid after NPTU.
Also, only college hours earned at the time of DEPing into the Navy count toward the tiered college kicker.
Any hours or degree earned prior to ship will not be paid, even if its in your contract.
I speak from personal experience.

Best Regards.