Looking for MongoDB Expert to help create query for report.

I need someone to help create a query for report page views for the month in from highest to lowest: One user Access Record: { "_id": "5x4YuEM3Ydj_C-YN", "_class": "[login to view URL]", "userPages": { "a3cbb34de70e2a3a69111b92f3bdc746": "url1", "94122ef86438464817bfb426564e836b": "url1/[login to view URL]" }, "expiresTimestamp": { "$date": "2017-11-15T12:38:37.318Z" } } User Page History "_id": "dRA_V3UuP-cehgfL*site_tk_9tOSAsjwqpgrG0I5", "_class": "[login to view URL]", "entryTime": 0, "userAccessBoundary": "dRA_V3UuP-cehgfL*site_tk_9tOSAsjwqpgrG0I5", "userEntries": { "1499945100682": "a86dc49051300046cf8a78a8e118e027", "1500262884108": "98631644265d33b64274c9a0e0a004f2" }, "expiresTimestamp": { "$date": "2017-08-12T11:25:00.682Z" } } User page has a bunch of entries, the value to those entries are actually the keys in user access record collection which are unique pages visited by that user. User page history id after * is a what we want to group by in this case: site_tk_9tOSAsjwqpgrG0I5 For All the user page history record who's id has this site_tk_9tOSAsjwqpgrG0I5, We want to get all the count of unique pages. and get them in order for high to low, also based on the month ( expiresTimestamp ).