Buttons and menus are named exactly as the app shows them.
Steps
Install for offline
The installed app opens without a connection, with your recent data kept on the device.
Keep working
Anything you change offline waits on the device. A small chip at the top counts the changes and sends them when you are back online.
If a change is refused
When the server turns a change down, a banner at the top says so.
See what is stored
Storage & offline shows what this device keeps, and lets you clear it.
Where: Settings › Storage & offline