assume cs:code, ds:code   ;dont really know what this does lol
org 100h
start:

mov ax,0B800h   ;video memory
mov es,ax       ;es register now points toward video memory

mov byte ptr ES:[0],218  ;the corner character to go on the top left
mov byte ptr ES:[2], 196 ;prints "-" next. this will eventually be the top outline of the grid
mov byte ptr ES:[3], 196 ; was trying to print another "-" but a red box appeared?

end start