Win32 application project, L2.exe source to start client with proper parameters, avoid HOSTS and l2.ini modifications and usage of .bat files.
Download Visual Studio 2019 https://visualstudio.microsoft.com/
Install Visual Studio 2019, make sure to include at least C++ package.
Clone the project.
Change the host (IP or DNS).
Change the icon if you wish.
Compile and have fun!