This might help - read it with the example given by Nesbox and refer to the Wiki :D
local red=0 local green=0 local blue=0 --r,g,b values are in range 0-255 --three consecutive addresses for --each palette entry --modify palette index 1 --by poking max rgb values into --its 3 addresses, making it white poke(0x3FC3, 255) poke(0x3FC4, 255) poke(0x3FC5, 255) function TIC() --palette index 0 is black by default cls(0) --hold button A (ie key 'Z') --to increase red component of index 0 if btn(4) then if red<255 then red=red+1 end poke(0x3FC0, red) poke(0x3FC1, green) poke(0x3FC2, blue) end print('This text drawn using index 1',0,16,1) end