Sometimes it's hit or miss with the "buttons." If you didn't know, you have to touch the bottom contact AND one of the three top ones. I believe to turn it on is the right contact.
The middle and left buttons (and of course like always, in combination of also touching the bottom contact) are to scroll right and left, and the right contact is to select.
In case you need to understand what the icons you scroll through are, the left most is the "dive planner", the next is your logged dives (#1 being your most recent), the next is the temperature and current mixture display, then the O2 percentage selector, then the "microbubble" level which determines how conservative it is when determining your remaining bottom time. A higher number (if I remember correctly) will cause you to go through more deco (or deco PERIOD, even if you are diving withing the limits of the standard table).
And trust me, she made a great decision. It's a great computer. I love mine. I only wish it did more than a single gas for multi-gas deco.
Hope it helps!