Common App Questions

There some stuff on the common app that I find confusing.
What do I put for final grade if my school uses semesters?
What are the credits for the grades?
Can I report weighted GPA even if my school reports unweighted?
If yes, are honors a 5 or a 4.5 for a weighted gpa?
If I want to list Martial Arts as a activity is that cultural or other?
Thanks!