Hi Gabriela,
The short answer is: you can’t. The default activities in that package don’t have an implementation for the document analyser.
I don’t know how extensive is your UiPath/Software development knowledge, but… an alternative could be creating a custom connector (Or building an API you could invoke from UiPath) with the exact scope you need to call from Vertex. Please consider it will add significant complexity to your implementation.
I personally am not so familiarized with Vertex, so sadly this is all the input I could give.
Parse and chunk documents | Vertex AI Agent Builder | Google Cloud