MS paint for the graphics. I spent a little time doing the squares and a few 'master terrain patterns' to go in them. Did a few 'master unit blocks', then just cut, moved, pasted, rotated as thing went on. Simple software, if a little time consuming.
The initial squares were done by drawing an X with line, then putting a box over it - the X tells you when it's square. Then remove the X. Then copy and paste a few boxes next to each other, then copy the strip and paste, copy the larger block of squares and paste, etc. until you have a block of squares the right size. Keep this saved as Table Blank (so that you can bring it up whenever you need it in future) then immediately save it again named as the battle - don't just use the original, you'll kick yourself. All plain sailing from there.