Alternator

To work on your own vehicle, you need a basic set if tools, standard and metric, wrenches and sockets. It's not feasible to buy one wrench for one job. I don't know the wrench size? If I grab a wrench out of the tool box and it is a little too small, I just grab the next size up. The discount autostores sells these tools in sets.

Take negative battery cable loose. Take serpentine belt loose. Take electrical connectors loose from generator. Take mounting bolts loose from generator. One of my databases, showed the picture below.

In the picture below, the electrical connector, you should be able to squeese with your fingers and take it loose. The charge cable has a nut holding it on there, need to use wrench or socket. That cable is live, that's why you need to take negative battery cable loose.

I don't know litre size of engine, note the text on the diagram below. The tensioner may have a bolt head in the middle of pulley, Put wrench on bolt, push or pull to take tension from belt.