For each slide, it doesn't matter /which/ of the positive/negative reaction stimulants you use, just adjust until the light on Emmet's helmet goes green or red, and then advance to the next slide.
Positive reactions: Stew, Music (both persist)
Negative reactions: Bacteria Tank (persists), Generator, Algae Cake
The two smells will neutralise each other.
You can keep trying with new memory maps until you get it right, and then the machine short circuits so you can't do it again.
My first try I got Emmet's card to read "Layabout", the second time I got it right