Hi Michael
Your photographs are going to be 2"x2" if you want 6 on one 6x4 sheet. You do not say whether you want 6 the same or six different ones but the method is almost the same.
1) open your photo and resize to 2x2 or photos if different
2) If there are all of one photo now duplicate it (find in image drop down menu)
3) Now select canvas size (find in image drop down menu)
4) Change the settings to 6"x4" and in the set of boxes select the top left hand one
5) click OK
6) you will now have a 6x4 image with your photo in the top left corner
7) select your duplicate and drag it over, placing it next to the one already there
8) repeat instruction 6 until all photos are there
9) flatten layers (found under layers drop down)
10) Print
stew
