ord personnel,
You will need a basic understanding of layers in photoshop but try
this:
With photoshop, open all the photos you want to combine.
Now you want to get all the photos into 1 file as layers. You will
use the first photo as your 'canvas'.
Now go to the second photo, select all, copy, and paste into the
first photo - it should appear as a new layer. You can now close
the second photo. - Do this for all the other photos.
Now you should have one photo open with many layers, each layer
showing your different photos.
Select the top layer, and use the eraser to erase all around your
friend - ie the background. This should expose the layer below it,
and another image of your friend. Now do the same for the layer
below, and so on.
gd luck!