Hello and welcome!
You've been given a 3 month project to design a slack clone (and you have 45 minutes to do it :D)
You have some functional requirements:
- There are organizations
- Organizations can have many channels
- Organizations can have many members
- Members may be occupants of many channels
- Members should be able to send and recieve messages in real time, to channels
- The organization's messages should be searchable
You are free to make any assumptions you like, beyond these requirements.