Step 1: Download "My Contacts Backup" in the app store. Click here
Step 2: Open the app. Go to Settings (Cogwheel in the bottom right) and change the Type to CSV (Excel). You can also configure what fields you want included in this export. Once you are done, click done in the top left hand corner of your screen.
Step 3: Click Export and then email to add your email address that you would like this export to be sent to.
Step 4: Open the Excel CSV spreadsheet from you email and save it as a .XSLX file.
Step 5: Import the data sheet. Here is how: https://crelate.zendesk.com/hc/en-us/articles/204278595-How-To-Import-Data-from-a-Spreadsheet