just 'Check for Updates':
and 'Update All':
You will now get a new 'Launch Browser' option in the Quick Start tab:
To see a demo of this feature see the following video:
Note that you must be using the latest version of ZAP (currently 2.6.0) and at least Java 8.
Version 2.6.0 does support Java 7, but this functionality requires Java 8. It’s worth noting that the next full release of ZAP will also require Java 8 as a minimum.
If you have any problems or questions about this new feature then please head over the the ZAP User Group.