I understand. For the man, I was trying a standard low-key portrait. Everything except the face (and perhaps some skin or contours of the body) is dark, while the face is light. The girl wanted to try a while shirt, which actually is not standard "low-key". The other look I was going to work on, but I didn't understand how to control the flashes well enough, was standard high key portraiture. There, the background and sometimes even the clothes are bright, often white, and the face (skin, contours) are the important (and sometimes the only) darker tones.
Normally, if you had your portrait taken at a portrait studio, the photographer probably would not aim for a complete low key or high key shot. Typically, it would be in color, with perhaps a neutral background. Lighting would be balanced and even, neither low key nor high key. In some ways, low key lighting is easier; it can be done well with only one flash.
For anyone interested, here are two (of many) simple youtubes on the subject, one on high key and the other on low key: