Answering Q2 first:
All images are rectangular, but if you want to do a 2D game then you may not want to be restricted to just square-shaped players and objects. So, the black background can be made "invisible" - all pixels coloured black are not drawn to the screen, and whatever is underneath is allowed to show through. As a result, you can have 2d graphics whatever shape you like. You're not restricted to using black as the transparency colour - use the "Set Colorkey" command to specify any RGB color you wish to be defined as invisible.
Q1:
If memory serves me right, the command your refering to is "Create Animated Sprite" (or is it "Create Sprite Animation"? Being mainly a DBC user, I'm not too sure). To use it, what you should do is make each sprite frame exactly the same size. Then, copy and paste one image at a time into something like MS Paint and work your way across the screen one row at a time. Save this new larger image, and when you load it as a sprite sheet, you get to specify how many columns and how many rows were on the image. So, if you have an 8x8 grid of frames, just specify 8, 8 as the parameters and DBPro will do the rest!
Hope this helps
RTR
"I wish I was a spaceman, the fastest guy alive. I'd fly you round the universe, in Fireball XL5..."