Just learning a VMC600 (yes, i know about 20years late)

Two questions...

1. Should air leak down the spindle all the time ?
I could understand when it was spinning, to block coolant ingress, but mine is blowing a huge amount of air continuously.


2. It's a Heidenhain controller
How to perform a tool change using the ATC ?
I see the code for it in some of the programs it has, but surely there is a manual button for this ?