Getting Started - ScienceHackerspace/Raspberry-Physics GitHub Wiki
First-time setup
To begin working with your Pi, connect a keyboard and mouse through USB, and a display through HDMI. Make sure your SD card is inserted into it's slot then plug in the micro-USB to turn it on.
Raspberry Pi runs on the Linux operating system which can be intimidating to new users. Upon booting, a fullscreen terminal will be displayed, and you will be required to log in. The default username and password will be pi and raspberry respectively. After logging in you will be able to enter Linux commands. As useful as the terminal is, it is sometimes helpful to have a graphical interface. The command startx will launch the graphical interface.
You will want to download any updates available for your Pi.