When and where am I required to run in rugby? NOOB!

[MadDog1999]

I was just wondering where and when do I run when I am playing rugby and not holding the ball so I am not just standing around the place? Do I just run with my teammates incase they need help or run against opposition to tackle for the ball? What do I do when a teammate has the ball? Like where do I run because I never see rugby players standing around the place.
Thanks

 

[Pieter Steph du Teague]

Depends what position you play.