How to retrain model?

HI All,

I am new to document understanding. I am doing some work on processing invoices using a framework I found on the Academy / Training section for document understand on this website.
The endpoint i am using for my model is

Now, when I process invoices, all of them go the validation station meaning that the confidence is below certain threshold. I understood this to mean the model ( doesn’t work well with my invoices?
Also if that’s the case, how do I retrain this model so that confidence in the model goes up and no manual intervention is needed?