Need help with nodejs and mongodb chat application schema design and query for private and group chat

Hi I am working on a chat application, I need help with reviewing the design of the message schema for private chat or group chat. Also, need help with the query to get the chat message between two people along with unread message count and last message of the chat..like any other chat application and same for the group chat. Like, show the unread message count to each user of the group and the last message sent to the group. Note: I won't be able to share the code with you. I will give you remote access to my machine. This won't be 100% coding assignment for you. it will mostly be guiding and query writing work. and reviewing of the MongoDB schema design for a chat application. If you have done a chat application in the past. please then only bid for the project.