During the upgrade processes you get beeping to indicate the firmware is writing - I guess it's a "don't turn me off" kind of thing. In normal operation, when turned on you should get a musical up scale, followed by three beeps. During that the front LEDs will flash a couple of times while the back ones cycle through the three colours for a short while (this is the boot-up sequence). After that your indications will be different depending on whether you are in Vision or NAZA mode as the aircraft tries to acquire satellites, but the standard Vision LED codes are on the crib card that came with your transmitter.
(Oh, and always remember to turn the transmitter on first, then the aircraft - reverse this to switch off.)