Yeah, gonna need more info than that to help really.
In a program you need a "T010101" for tool 1, "T020202" for 2 and so on.
Since the machine has multiple turrets, it needs to know which turret you're indexing.
so, G13 T010101 will index the upper turret to tool 1.
G14 T040404 will index the lower turret to tool 4
In order to index the machine needs to be on the "machine limits" and you can do so by programming:
G13
G0X100Z100 (INCH MODE VERSION)
G0X10000Z10000 (METRIC MODE VERSION)
T010101
G14
G0X100Z100 (INCH MODE VERSION)
G0X10000Z10000 (METRIC MODE VERSION)
T010101
M2