ok i'll guess here. our soaker tub at home has air bubblers on bottom. so maybe the first button. middle 2 is how high or low they blow. last button for the jets on the sides maybe? that's how are tub is. i could be totally wrong. ours also has buttons to separate the jets meaning side vs low back middle back and neck. those neck jets suck. you move your head you are spraying the wall in ours. lol i'm just guessing, but if you are there fill it and start pushing buttons.