The tones are -

1st tone (high, level, long), indicated by a horizontal bar e.g. ō
2nd tone (high, rising, medium), indicated by a rising accent e.g. ó
3rd tone (low, dipping, long), indicated by a dipping accent e.g. ŏ
4th tone (loud, falling sharply, short), indicated by a falling accent e.g. ò