Trying to create my own loss function, but no documentation on low level API

[michaeljehan]

Hi, I noticed that there has been a major update from version 4 to version 5, there are some changes to the functions and no more documentation on low level API, I am trying to create my own loss function other than having PDE and BC loss function which i usually do with using low level API, is there any way you recommend to do this?