How best to trigger a process when Opportunity Status changes to Closed Won?

I want to trigger a process with the Opportunity stats changes from anything to Closed Won.

The process only needs to run when the status is set, not on every save after that.

My main question is how to get this to trigger ...

A little more on this...any thoughts would be welcome....

We need an admin person to preform about 5 different tasks when an opp is created (do this, file that, check something ...etc)

I am thinking to create Actual tasks within the Task Module. or would it be better to create some process author Activities instead?

Thanks

Greg