OK I'll try to do this as painless as possible:
If you played Minesweeper then it should be a little easier to understand.
1st you see the numbers on the side and top? What these numbers mean is the number of consecutive spaces in the row/column. So for instance if it is a 10x10 grid and one of the rows/columns(r/c) says 10 then the whole r/c is "shot" out. Of course if the grid is 15x15 then 10 will be consecutive and 5 will be marked. If it says 0 then it means that the r/c there has nothing to be "shot" out regardless of the grid size and you "mark" it with the other button. If it is say 1 3 4 it means that in that r/c there will be one space then three spaces then 4 spaces somewhere in that row. Buy looking at the numbers on the sides and top you can figure out where you should be "shooting" and "marking" your grid. Later on it gets crazy because you have catipilers hiding the numbers and grid suckers that erase or place x's on your grid. You get power-ups to help: a cross section will clear a whole row and column, the bomb will blow up a 6x6 area, and the hammer you can bash as many 3x3 areas as possible in 5 seconds, an eye will visual show you the picture for 5 secs. If you're just starting out set the DIP switches to slow time and easy this will help a little. It's one of my favorite games as of late and loving it.