How to filter Json data/API?

I have an API in JSON format, and I want to filter the data so I only display parts of it and not the whole source. I'm basically looking for some code that will recognize a pattern I define in the file, then selectively transform the pattern into an XML/ATOM feed, and ultimately display the transformed data on my UI interface (my screen/web page). So far in node-red, I have the http requests and the XML/JSON nodes. But what I'm very uncertain about is how to select only parts of the JSON file.

I'm brand new to programming. Node-red has been very helpful so far.

Any help would be appreciated!

Can you post your flow, or some example output from a debug node ?

To filter data from json is relatively easy with JSONata, which can be found in the change node.
But you might want to watch some tutorials on the workings of JSONata, it is extremely powerful, but might be a bit confusing at first.