Prerequisites: You have MS Teams installed on your machine. If not, you can submit a request to have it installed. To find out if you have MS Teams, go to Start and type Teams in the search box, it should look like the icon above.
To have a call-in number, you must request Microsoft Teams Conferencing through the Service Catalog. It will also work if you have Skype for Business Conferencing.
Open Outlook
Go to Calendar
Hit New Meeting
Hit Teams Meetings
It will then populate the meeting with the MS Teams information.
If it does not populate with a MS Teams Conferencing number, you will need to request Microsoft Teams Conferencing number through the Service Catalog on the helpdesk site. You do not need a call-in number, but it is useful if members joining the meeting do not have MS Teams on a device.