Task switcher in lollipop topic

I suddenly feel like a total noob. I've just upgraded to stock lollipop.

I can't decide whether it is a bug after upgrade or whether I don't have a clue.

I cannot access recent apps. I've tried double tapping the home button, sliding up from the home button, (thought that was the Google Now shortcut) and neither seem to do anything. I really miss task switcher. Can someone tell me whether I'm doing anything wrong, or is there a bug in the stock rom?

Many thanks,