Slacker

Just took delivery last night.
Remember the DS saying that Slacker would need to be activated but don't remember the how part.
Have spent too long searching past posts!
Does Tesla do it so that it automatically starts working a certain number of hours after delivery(like my phone app)? Or do I need to do something?
Thanks!

Well, it seems to have spontaneously started working when I got in the car this morning.
So the Slack has been taken up. Amazed at how good the system sounds with Internet radio.