Multi class product classification according to description of product

I have some products, along with their description. I wish to assign USPSC code to each product. This would require classification on 4 levels. All the examples I could find online were that of sentiment analysis, which is binary and therefore different from my problem statement here. Could anybody guide me to some resources? Or how the binary classification can be extended to multiple classes so I can pick keywords from product description and assign them categories? Thanks!