There are a number of reports that you can use to create your table for importing.   If you are working on creating connections with team members, then use the "Volunteer Teams with Volunteer Team Members and Contact" report type to get both the Contact ID and Team Member ID.  Reports are helpful if you are seeking contacts based on their related records, such as is a member of a Volunteer Team or has a connection to a specific volunteer opportunity.

The three most important aspects when creating a report for use in importing are:

1. Include the Contact ID column in the report.  The Contact ID is the Salesforce ID for that record and is a 15-18 digit alphanumeric number.  If you are also wanting to associate the Connections with a Team Member, you also need the 15-18 digit Volunteer Team Member Salesforce ID.  Note:  The Salesforce ID for Team Members is not the VTM-0000000 id.
2. Export as a .CSV file
3. After exporting the report, open it and remove the footer from the report.  The footer is the last 5 lines that appear after the last row of data and begins with the report name.

See this post for instructions on creating a basic report to use for this purpose.

You can use an existing or create a new view of contact records.  Remember when creating views you are limited to filter based only on the Contact fields.  This approach is helpful for locating contacts associated with a specific organization or have complete orientation, etc.

If you are using views and selecting the "Create Connections" button, you'll be able to skip the first step of the Wizard.

3.     Use the lookup to select the Volunteer Opportunity.   Once the Volunteer Opportunity has been selected, then use the Occurrence lookup.  The Occurrence lookup will be filtered to all the Occurrences associated with the selected Volunteer Opportunity.

4.     If the Volunteer Opportunity and Occurrence are a To Be Scheduled opportunity, then the Date, Start Time and End Time fields will be presented.

5.     Designate the Status and Attendance Status for the Connections you are creating.  Remember if the Date & Time are in the future then use the Attendance Status = Please Verify

Once you click on "Create Connection" then go to the Occurrence and confirm that all connections were added.

System Admins that wish to enable this functionality can follow the steps at this link.