I can help translate if you need help. Most will come with a suggestion of units of npk per acre. For reference 6-12-12 would have 6 units of nitrogen per 100 pounds and 12 units of each phosphorus and potassium per 100lb. And the local co-op or your co extension office can get it sent off for you.
Extension office or nrcs can help. But biologic produces results that are super easy to understand. Even has rates per acre and per 1000 sq feet for small plots.
If you want to do it the simple way order a couple of them from the Whitetail Institute. Yeah, it's more expensive but your just talking maybe $5 more and you don't have to drive anywhere to get the kit. Their results can be emailed to you once you send them your bag of dirt and it's easy to interpret since it's written for hunters rather than farmers.