You accrue 2 ½ days of leave each month for a total of 30 days per year.
Subject to the approval of your chain of command and the requirements of your unit's mission, you can use this leave at your own convenience for any purpose you choose (if you do not use all 30 days, the excess carries over to the following year).
A row on your LES is reserved specifically for leave - check this line each month to see how much leave you have available.
As a new Soldier, you will have very few days of leave accrued.
In the case of emergencies or special circumstances, your commander is authorized to advance you a certain number of days.