ld hl,&0603   ;6 = ROW, 3 = COLUMN
call &BB75              ;set text cursor according to HL

ld hl,Message
call PrintString

ret  ;return to basic

Message:
byte "Hello",0

PrintString:
ld a,(hl)   ;read a byte from the string
or a        ;check equality to zero
ret z       ;if equal to zero, we're done
call &BB5A  ;print accumulator as an ascii char to screen
inc hl      ;next char
jr PrintString