Your first day with a new Mac: the get-started guide for Windows users

Update: some keyboard characters corrected:

Just got a new Mac for Christmas and feeling a little bewildered?

The Activity Monitor, found in Applications > Utilities, provides an overview of what resources are being used on your system, and gives you more granular information about which processes are doing what. If you know what you're doing, you can use standard Unix commands in Terminal (Applications > Utilities) to kill specific processes using their PID.