and how people forget why forums exist: to help each other. If your answer is ‘search it’, or ‘RTFM’, you have completely misunderstood what fora and communities are about and it is better not to answer at all to safe yourself and your readers the time.
- make a new calendar in the calendar app.
- A tasks list with the same name as the calendar will be created
- Share the calendar with any (new or old) users who have an account on your Nextcloud.
- Users can now see (and edit if you gave them that permission) the tasks in the task list in the webinterface.
To use the task list offline, or in apps, you’ll have to add the caldav URL to your app of choice and sometimes (like on Android) install a separate task-app.
The steps to achieve what you want are indeed not logical and straightforward and it is good that you ask here on the forum. Maybe it incentives devs to make this feature more end-user friendly.