Watch a quick video showing you how to view multiple diaries, and scroll down for more information
I don't have this option...
You will need to be on senior engineer role level or higher to see this. Please ask an owner/manager to set your role level appropriately
You may also not see this if you have updated your app to the newest version, please delete the app, then re-install and you will see a prompt after logging in to turn on the multiple diary feature.