This is a java program and so you need to install the java jre and jdk programs before you can run it.
For Windows system, you may just double click the wiihid.jar to launch it.
Linux System Settings
For Linux system, it must have been installed with bluez and bluez-util. Furthermore, assign hid device access permission to ordinary user by adding a file (say, 90-hidraw-permissions.rules) in the folder "/etc/udev/rules.d/" with following content:
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", MODE="0666"
Then, issue the below command in a terminal:
sudo udevadm control --reload-rules
For older Linux system like Red Hat/Centos 7 or below, you need to install bluez-compat and set permission for ordinary user to use hidd by issuing the below command in a terminal:
sudo chmod a+s /usr/bin/hidd
If you cannot do it with the above method for the Windows system, you need to download wiihid.sh and enable its execution mode by issuing the following command in a terminal:
chmod a+x wiihid.sh
Then, you could launch this program by clicking on the wiihid.sh file. Alternatively, you issue the following command in a terminal:
java -jar wiihid.jar
Apple MacOS Settings
Watch the demo videos which show how to connect a wiimote to the Bluetooth of the respective operating systems and use it in many different ways. In particular, you may use the Wiimote as a mouse by pressing 'B' and '+' buttons together. To move the mouse in the Left, Right, Up or Down direction, just rotate the Wiimote in the corresponding direction.
If connected to a Nunchuk, press buttons 'B', 'C' and 'Z' together to use the Nunchuk's joystick as a mouse. In the mouse mode, press buttons 'B' and "Home" together if you want to use a virtual keyboard. For Linux system, a software called florence Virtual Keyboard needs to be installed. Right click button to show more choices for different operations.