Here is a simple guide for my record. I learned it from another player.
First, to play the Wii game on PC, I need Dolphin Emulator. I download it from its official site.
The latest version is Dolphin 5.0-18498 build. I just download it and unzip it to my PC.
The next step is to have my old Wii remote. I found it in y storage room. I store all the old game stuff there. Put the new batteries into it.
Launch Dolphin.exe which I extracted in the first step. Click Controllers to pop up the Controller Settings.
Select Continuous Scanning, and click the Refresh button next to it.
Then press the red sync button under the battery cover of the Wii Remote.
Done.
Now I can play Wii games with the Wii Remote on PC through Dolphin Emulator.