No, you do not need to remove the fan shroud. You should be able to get at it. Follow this procedure:
Belt Routing without a/c:
Belt Routing with a/c:
HOW MUCH TENSION ON THE BELT AFTER BEING INSTALLED
The guide says to measure the belt tension with a belt tension guage.
to be honest, i've never used one. I usually tighten it until it will only move up/down about 1/8in either way.