Urgent: Successfactor audit trail, actions definitions

Hi,

Can you please help me to explain a few 'Action' definitions. What does following mean?

1. Skip?
2. Manual Modify?
3. Manual Sign?
4. Manual Route?
5. When will someone typically use 'Re-route a completed document'?
6. Modified (what is the difference to 'Manual Modify')?
7. Final Form?
8. What is v4admin?