What design pattern can I use to walk through the documents from a web client?

I am using Python and pymongo
I am able to save documents and to retrieve documents by id
I would like to be able to browse the database after the documents are sorted in ascending order using a last_accessed property. I suspect that an idex will take care of the ordering but I need to learn how to use indexes
When the document was displayed this field is updated and the next document should be retrieved by the client.

what mongodb specific methods can be leveraged for this type of browsing