I'm noob with PICO-8 and wanna play "Mary had a little lamb" using only beeps from code. Not using sfx editor, not using music.

however, i dont hear any beeps. Whats wrong?

	print("Press arrow keys ",12,64,0)
        ID=0

	if btnp(0) then sfx(id,"E-4")
	  elseif btnp(1) then sfx(id,"E-6")
	  elseif btnp(2) then sfx(id,"E-7")
	  elseif btnp(3) then sfx(id,"E-5")
	end

That is not how the sfx function works.

... I think maybe you're accidentally trying to do a TIC-80 tutorial on a PICO-8?

Anyway, so far as I know, you can't do what you're trying to do.

The SFX function only plays sounds from the sound editor.

(I do wish you could at least generate simple tones from code.)

Yes, i tried a TiC-80 example, didnt work.

>> generate simple tones from code
which seems possible in TIC-80.