Very simple, create a bat file, for example openwechat.bat, then copy the following content into the file:
@echo off
start "" "C:\Program Files (x86)\Tencent\WeChat\WeChat.exe"
start "" "C:\Program Files (x86)\Tencent\WeChat\WeChat.exe"
exit
Remember to replace the path to your WeChat.exe with the actual path on your computer in the content above, then double-click to launch 2 WeChat instances. Of course, write as many lines as you want instances, I'm sure you understand.