Force Quit Applications in iPhone

[Sdahe]

Hello guys...

Sorry for this dumb question but I'm new to iPhone... How can I force quit or shut down running applications in the iPhone?

 

[Tallest Skil]

Holding Home until I get back to the Home Screen usually works and just hitting the Power button to lock-unlock sometimes works.

 

[Sdahe]

Holding Home until I get back to the Home Screen usually works and just hitting the Power button to lock-unlock sometimes works.

Thanks!!!...