I try to add tasks or make changes to projects but there is no way to save changes.
If you tap on a task, then on the pencil icon at the bottom, you enter edit mode and can save the changes by confirming them with the "tick" icon in the top-right corner.
Same applies to projects - please use the icon in the top-right corner to save any change you make when editing the project's name, color or indent level.
Ok, now i see my problem. The "√" at the bottom, marks the task complete. I assumed that the "√" at the top was for the same purpose, so I avoided clicking it. Now I know that the "√" means two different things.