Use case tables-Activity diagrams-Event Table

According to my tutor i noticed that my activity diagram was needed some corrections.I change my activity diagram and i have created another 3 activity diagrams.Moreover i have create one main use case and i started the first individual use case "create new offer" .I have spend many hours to understood how it must be done and what steps must be include.I believe that i have mistakes but i would come back to that point after the next tutorial lesson.In addition i created also an Event table which is also need corrections.