New to WebDynpro JAVA

Hello people!!

I'm new to WebDynpro Java, so I have a couple of questions to you gurus:

1) I have a little trouble working with different BAPIs at once. Let's say, I created models, corresponding to various BAPIs to do different things, like validating inputs, create a sales order, etc. So, how do I work with them? 'cause I created a custom controller mapped to the ZBAPI_CREATE_SALESORDER, and it works great, but how do I work with the other BAPIs if I have one to validate the materials, or validate the quantity, and so on? how is that mapping done?

2) On the same note as the question before, I looked for information on adding a matchcode to the webdynpro, but it is also done mapping a field to a Model, so if I have already mapped the view to a custom controller, how do I map it to the model for the matchcode?

Sorry for my english, I hope I was clear enough.

Thanx.

Jesus