ERPNext API using PHP

This week I managed to perform CRUD operations for Customer, Items and Sales Order by connecting ERPNext API using PHP. Once I successfully managed to do one of the operations the others become easy to do because the code is actually quite similar and I only have to change one or two lines of codes to make it work. But, I faced a problem with Sales Order because in Sales Order it needs to grab the data from Customer and Items table. Actually I only make a simple and silly mistake which I do not realized until Dr Shawn show it to me. With the help from Dr Shawn, the problem has been solved. After that, Dr Shawn briefed me about the next step that I need to do for the project and he guided me how to work on the things step by step.