Hello @joyryde,
Thank you for contacting the support and sorry for any inconvenience that might have been caused due to that.
Rank Math takes the Schema data from your product pages automatically and turns it into Schema-ready content. Likewise, the aggregateRating and review fields are taken from your actual product reviews that your buyers/customers leave on your products.
https://i.rankmath.com/Ni50EF
If you don’t have any reviews yet, that is going to show up as a warning in the Schema testing tool. That’s because Google will actually look for those fields.
Please acquire some reviews and ratings to get rid of the aggregateRating
and review
warnings.
You can fix the SKU and availability issue quickly as well: https://i.rankmath.com/wtM5aM
To fix the brand
warning, head over to WordPress Dashboard > Rank Math > General Settings > WooCommerce and choose from any of the available fields to use as your product’s brands.
https://i.rankmath.com/N1Txmh
If you want to use a custom value for your Brands, you can do that using Rank Math PRO:
https://i.rankmath.com/OFoEnt
For the GTIN, ISBN, MPN issue, you can fix them by switching to Rank Math PRO as well since it includes even more options for WooCommerce than our free version:
https://i.rankmath.com/OFoEnt
For the priceValidUntil
warning, you have to either ignore that or add a sale price with validity to get rid of it:
https://i.rankmath.com/cMqAAH
Hope that helps.