Answer:
Enlistment bonuses are paid to you through your Direct Deposit after you have successfully completed all training requirements YOU agreed to complete within you initial enlistment contract.
If you are to receive a $20,000.00 sign on bonus for a 5 year enlistment in a specific job, you will receive $10,000.00 (minus taxes) once you have completed your training requirements and have in-processed in to your first duty station, the remaining $10,000.00 will be divided up and paid on the anniversary date of the initial bonus payment for the remaining 4 years. ($2,500.00 a year minus taxes for the remaining 4 years)