At least you'll be well prepared and know what to expect with all those questions ;-D!
The dive plan will greatly depend on the conditions like visibility and currents. But of course the presence of the Sharks and Mantas and other great stuff, too. On a regular dive, once you're at the bottom, usually sheltered from the currents and anywhere from 20m/60ft to 30m/100ft, you'll hover around over the gentle slope. While you do that, stay close to each other. When you see a first shark, don't try to approach or follow it or make too much noise to signal it to other divers, as it will simply swim away - faster than you can...it's them who decide if they want to see us or not, so rather stop and wait, hang on to a rock if needed because there might be others following to check you out! If nothing else shows up, you will most likely continue your dive either drifting with the current along the Island or making a circle from the deeper to the shallower water. There are several points of interest at the shark dive site, like for example a cleaning station for other animals like Mantas. Just follow your guide and enjoy!