Motion Tracking Doubt! help needed Urgent

hey i have been trying to learn 3d motion tracking using blender i have a good understanding now thanks to CGmaters in-depth guides but… however i do seem to be confused by the different Motion Models available in blender under the tracking settings as we all know there are:

1)Perspective

2)Afine

3)Locrotscale

4)Locscale

5)locationroation

6)Loc

how do these work and when should i use these to get a better track? 3 to 6 is understandable but it would be nice for someone to explain this better!

Thanks A ton!

Here is a video about the modes: https://www.youtube.com/watch?v=WLSGG7sDEac

00:53:03 - Affine motion model
01:00:19 - Perspective motion model