The patch will update and improve your game and fix any errors that were in the game when it was released. I would recommend downloading and installing the patch.
All you need to do is download the file from the downloads section of our website and when it has downloaded you run the file and follow the instructions.
This is probably asked in the wrong forum as well as this is mainly for the graphical and user interface aspect of the game so I'm closing this. If you have any further questions about the patch then ask away in the General Questions for Football Manager forum.