Q: Do I need to anything special to switch my wireless mouse?

Hello there, IslandGirl1501.

To pair up the new mouse, the steps in the following Knowledge Base article should help:

Bluetooth: How to set up your Apple Wireless Mouse or Magic Trackpad

http://support.apple.com/kb/ht2845

Specifically the "Setup your Apple Wireless Mouse":

Set up your Apple Wireless Mouse

1. Open Mouse System Preferences by choosing System Preferences from the Apple () menu then choosingMouse from the View menu.
2. Click Setup Bluetooth Mouse in the lower-right corner of the Mouse preferences pane.
3. Turn on the mouse by sliding the mouse power switch to the on position. The indicator light above the power switch glows steadily for 5 seconds to indicate the batteries are good.  After that, the indicator light should begin to flash to indicate the mouse is in discovery mode.
   Note: If the light on the bottom of the mouse does not glow or flash when you turn on the mouse, make sure the batteries are properly charged and installed.
   
   Figure 3, above: Slide the Magic Mouse power switch up to turn it on. Note: The power switch on the Mighty Mouse and Apple Wireless Mouse power switch is in the center on the bottom of the mouse.
4. After five to ten seconds, the mouse name should appear in the Search preferences.
5. Click Continue. The Setup Assistant will try to pair with the mouse.
6. When the computer and mouse have successfully paired, the Mouse System Preferences will expand to show all configurable options and battery level in the lower-left corner.

Thanks for reaching out to Apple Support Communities for answers to your question.

Cheers,

Pedro D.