Rather than think in terms of people it might be easier to talk about necessary skillsets. for instance, you must have adequate camera work, lighting and sound. Depending on their background, one person might be able to handle or at least supervise all three roles. Similarly, someone has to be the director, but again, depending on that person's background and the complexity of the shoot, the director might also be able to handle some other role such as handling props.
To really figure out what personnel you're going to need, you're going to have to have a finished script. A detailed script (storyboards may seem like a luxury, but even crude ones can be huge timesavers in terms of helping envision how scenes should be set up and in spotting potential trouble spots. If you don't know what a storyboard is here you go
) is your roadmap and studying it in advance will give you an idea of what resources in terms of materiel and personnel you will need.