How to enter Purchase order and create Sales Order using API

My team has been using desktop Sage 100 (2021) to enter purchase orders to generate sales orders, but we would like to do this via API. 

https://help-sage100.na.sage.com/2021/FLOR/index.htm#Program_Listings/Program_Listings_Overview.htm?TocPath=Program%2520Listings%257C_____0

This doc is not too helpful.