Page History

...

1. Backlog: when work is created, it will come to this status first. From this status you can move the work to the another statussesstatuses. 
2. To do: work has not started (work can always move back to this status);
3. In progress: a developer builds & unit tests their own work to meet acceptance criteria (work can always move back to this status);
4. Review: a peer reviews any code & functionality;
5. Done: the work is completed without deployment needed (Resolution "Done" is set automatically); or
6. Canceled: No further work will be done on this issue, it is not required anymore or has become obsolete (a pop-up will allow filling the mandatory field Resolution)
7. On hold: 

In Progress  When starting to work on a ticket use the 'Start progress' button, ticket will automatically be assigned to the current user.

From all statuses you can always go back to status  'In Progress' ,  use transition 'To In Progress' for this 

...