How offline work flows
Think of the phone as holding a copy of the project:
Down: sync brings the project's setup to the phone - sites, forms, tasks, contacts, beneficiaries and the project plan. Do this while connected, before you go out.
On the phone you fill in forms, add contacts and beneficiaries and update tasks. Each item is stored under Saved until it reaches the server.
Up: upload sends what you saved. Do this when you are back on Wi-Fi or mobile data.
Sync and upload are separate actions unless you switch on Auto Upload (page 5). A phone can go days without a connection; just keep it charged and do not sign out or uninstall the app while items are waiting in Saved.