I have a 97 ford taures 6 cyl that the drive belt broke. The small free wheeling pulley looks shot. My plan?

is to replace the pulley and belt, but not sure I am capable. I have removed the small pulley(was already loose). I have the diagram for the belt, but someone told me I had to use a tool to loosen the tensioner. Do I loosen the bolt holding the tensioner on, or do I just try to move it?? If I loosen the bolt, then do I move the tensioner back to original position(and how do I do this?)after putting the belt on. Sorry if not clear, but it's the only way I know how to describe. Any help will be appreciated. Thanks