Where do I connect a hose to charge the air conditioner on a 2001 focus

You need to connect it to the accumulator. It is in the fender on the passenger side behind the headlight. Jack up the passenger side and look up from the bottom infront of the passenger side tire.

There is some metal lines that has a black cap over them kinda like a valve stem cap like you have on tires there should be 2 of them remove them and thats where you connect them