Emulsion comes bundled in two bottles, base and activater. Start by reading the instructions on the bottle. My instructions say to fill the activator 3/4 of the way with water so I filled it to about the top of the label, shook it up well, and mixed it into my base. Once mixed the combination turns green.
The mix is photosensitive and toxic at this point so don't taste the green ooze and be sure to take care of it under light conditions. This particular brand isn't too delicate and doesn't require a dark room for mixture or application. Don't leave the cap off the bottle and be mindful of the type of emulsion that you buy.