How do you invite friends to the Halloween 2018 Google Doodle?

After starting the doodle, there is a Host Game button in the bottom right:

After you click this button, it will ask if you want to create a private match. Click yes, and you will be prompted with a screen with a link you can give to your friends:

On your friends end, it should look like this after they navigate to the link:

Notice how there are now two ghosts on the screen, and it says 2/8 players ready. When you are ready, the host presses the start game button and you and your friends should load in. I tested this locally with two different tabs in Google Chrome and it seems to work.