Google product feed setup help

[Captain Weak Beard]

Any reputable professionals out there who can help get my product feed setup? I've tried a few tutorials and so on but not having any luck resolving the remaining issues.
Using Business Tech's Google Merchant Center v4.5.2

 

I've reduced some of the errors, but I cant figure out how to fix the remaining ones in the image. Some I can't work out how to solve, like 'product type' or two of three references need to be present, but some products don't have a UPC (I've got EAN's for the majority). There isn't any where to enter MPN's or the Brand in Prestashop that I can see.