You will have to supply more information regarding the type of Bluetooth device and Wii remote you have .. also what stack software you use.
Once your PC recognizes the WII remote through whatever Bluetooth software you have you must CONNECT the Stack software to the Wii remote.
Once this is done successfully, once you start Freetrack, you are correct in that there should be an Option for Wii remote in the Source Section, where DEMO once was.
**** Should this not be the case then you will have to look at your BTooth connection, stack software and Wii mote being the issue. There have been issues where Wii motes can connect but not operate owing to certain incompatible Bluetooth Dongles.
Your Wii Mote should BLEEP when it connects to Freetrack and the program should show your Battery Life in a %. Once this has happened you should be able to press start and point your IR LED at the Wii mote and see the dot.
***** Should this not happen then double check your IR source to ensure the LED is working ( Look at your LED with a Camera Phone - Most have no IR Filters - One quick way of checking your IR LED)
ALSO ... make sure that BEFORE you press START, goto the MODEL section and select the appropriate Build that you have .... be it 1 3 3 or 4 Point.
Selecting the incorrect model here may also cause the LED not to show.
Hope this helps ... All I can think of just now with so little information.
Work through your items 1 by 1, eliminating whether they are functioning or not on their own.
Good Luck