Please help, as part of a college project I am trying to use the RPi B+ to take a photo when triggered by a pir sensor. I have practically zero experience with using a Pi and not sure of many things

Where do I start? how do I open a file to save the code onto so it doesn't disappear when I turn it off? is there a viewer on the RPi that will show the pic taken? Basically im lost as to how to best start this and need some advice for a dummy. If anyone can advise me that would be amazing.
Does anyone know if there is somewhere i can go and meet some experts in person?
any advice would be greatly appreciated
K jones