One of the most powerful tools in Google Calendar is your ability to invite others to an event. To set up an event with multiple people, just start as you normally would. Find the date on your own calendar for the event and click on the date. Type in the name of the event, set a time if that is relevant, then start typing people’s names in the space that says “Add guests”.

As you type names, Google will search through the listing of email addresses (remember, Google has its roots as a search engine!) and will bring up choices. Google will also search your contacts, as there is a reasonable likelihood of you inviting people within your contacts list to an event. 

You also have the choice with adding guests as to whether or not Google Calendar will deploy an email to them to let them know about your event.