No the play mode is replaced now by the campaign mechanics.
You now need to create a campaign, in order to play on a map.
First you can create a campaign on either the platform, or in the editor,
Then you add your maps you want to play on, this can also be done on the platform, or the editor,
Having that done, you can open one of your campaign maps, and are able to invite your players as usual.
The button to invite your party can now be found in the new yellow toolbar on the very bottom.
The best thing about the new campaign mechanic is that when you start making changes to your map, it will be saved separately as your "campaign-version" of your map. This means that you, or your players can mess up your map as much as you/they want, because the original map will stay untouched.