How to add a sync gateway user to get a doc or list documents from an existing bucket data (travel-sample)

It has been observed that it is not obvious to the beginner that the sync gateway user should be created with admin_channels as '*' to read or list the documents with an existing bucket data like travel-sample.

In the below document, it would be good to cover the use case snippet to just have access to all documents by adding admin-channels to '*' and then selectively how to restrict the access to certain documents by pointing to the channel creation documents.
https://docs.couchbase.com/sync-gateway/current/get-started-verify-install.html

Example:
% curl -X POST "http://localhost:4985/traveldb/_user/" -H "Accept: application/json" -H "Content-Type: application/json" -d '

'

List of docs:
% curl -utest5:test123 http://localhost:4984/traveldb/_all_docs?limit=20

Get the existing doc:
curl -utest5:test123 http://localhost:4984/traveldb/airline_10