In Google Calendar, edit an event that you have created
1) Be certain to name the event something descriptive (from the other participant's perspective). Naming the event "meeting" doesn't help other people at CA understand who is meeting in a particular room, or who their meeting is with.
2) Click Edit event >>
Chose to add a Room
1) Click on the Rooms, etc, link
Reveal the buildings that hold the rooms your are interested in
1)Click the drop-down triangles
2) Add all the rooms that might work for your Event
Click the Find a time link
1) Find a time
Select a time that works for your Room and guests.
1) You can drag the box up and down, or dial in the beginning and end times till they fit.
2) Be certain to remove the Resource Calendar feeds that you don't require, before saving the event.
3) Guests added to the event have their free/busy time revealed in this tool
Clicking on the user icon toggles them as "optional."
1) Sometimes a person should know about a meeting, but doesn't need to go.
2) Choose to allow guests to modify an event, so that they can tweek the start and stop points. Not doing so will generate more emails for you.
Add a Description and Embed an Attachment
You can search your Google Drive for an agenda to attach to the meeting. Everything is in one spot for the attendees. Afterwards, add the meeting notes in that document.