Joining a Zoom meeting or webinar is generally as easy as:

• clicking the link in an email you received from the host, 
• clicking the Join link in the Zoom section of your Canvas course ,
• clicking the Join button in your Zoom application, or
• clicking Join Meeting on the Cornell Zoom website and entering the Meeting ID.

The following video from Zoom gives the basics about joining a Zoom meeting.

For more details, visit the Zoom's documentation, Joining a Zoom Meeting.