Are we talking script tiles? Or just person events? Unknowns are not necessary (usually 03, but don't tend to have an impact) and the var is whatever variable is going to control your script, if it is a tile. Person events don't need them.
The var number allows script tiles to run if and only if the var equals the value. The only safe vars are 4000-40FF and the original functions of the ones in the game are listed on the link I gave you last post.