To get documents from Tamino, use the query() method and use the iteration to get to the individual documents returned.
To delete element or insert a new element you simply use DOM methods on the individual document obtained via the iterator and use the update() method to update the entire individual document back to Tamino.
For documentation on DOM1 (which the TaminoClient API uses) download the DOM SDK from here. If you use the TaminoAPI4J (which I would recommend to you) then you can have a look at the DOM2 documentation here.
hope this helps,
Stuart Fyffe-Collins
Software AG (UK) Ltd.
#webMethods-Tamino-XML-Server-APIs#webMethods#API-Management