1.  Open the Excel Spreadsheet or Google Sheet

2.  If not already sorted, sort the spreadsheet so that the emails you want to use for your list are in a row.

3.  Select the desired emails and use Command C (⌘ C) or go to the Edit menu and pull down to select copy.

4.  Go to https://contacts.google.com/

5.  Log into your Gmail account

6.  In the upper left corner, click on "Create contact" and select "Create multiple contacts".

7.  Click on "No Label" in the top right of the pop-up to create or add a preexisting label.

8.  Click on the "Add names, email addresses, or both" box to make sure your cursor is in the box and hit Command V (⌘V) to past.  This will paste all the emails that you copied previously to this box.  

9.  Click "Create" to add the group.