setting the view correctly

Hi, can someone help me with setting the view in the way I and during it explain how the parameters of the view effecting the view:
Im using `lookat`,`front` and `up`

Here is a pointcloud exmaple:

What you see here is a pointcloud of grayscale image with a bright image of a person in it's beginning. This is a point cloud of a hallway where the person is in its start. So I want to set my view just a few 'meters' behind the hallway start (looking from the persons back view), how should I change my parameters?

The second question is how would I change my parameters to create an angle "little bit righter view ", "little bit lefter view", "little bit abover (more from above) view" ?

Thank you in advance.