1. Make sure that your skugrid account is set up and configured already - https://www.youtube.com/playlist?list=PLg7nwHnJeAmNW33IVSWvt7F7Md1iFU6ai
2. Import Your Current Items into Skugrid -- here's a video on importing (the layout has changed a bit but the concepts are the same) -- Click Import/Export and then choose Import from Marketplace https://youtu.be/hpuaczIQobY?t=29m36s
3. Now Export the CSV from Skugrid so that it is in the proper format that skugrid needs.
4. Open the CSV in a spreadsheet software (prefer not to use Excel as it often will mess up your CSV) I recommend Google Drive/Sheets, OpenOffice or LibreOffice
5. Add supplier urls to the vendor_url column add the supplier variation to vendor_variant column (this has to be exactly as the supplier has it) if there is one.
6. If you want to use Compare Item URLs go to the autoCompare Column and change all of the 0s to 1s. Otherwise leave them at 0 as it is optional. There are reasons to use them and not to use them - see here for more info so you can make the best decision for you - https://www.facebook.com/video.php?v=807206851840
7. Save the revised CSV to your computer (make a copy) so that you have your original CSV to revert to if there is a mistake.
8. Go to the Advanced Button and click Purge All Items -- this will remove all items out of your skugrid account.
9. Go to Import/Export and click on Import CSV
10. Browse for CSV file on your computer and upload it.
It will take time. CSV imports can take hours to finish processing, so just leave it there and continue your work in another tab or window until it's complete.