Prerequisites

• Visual Studio 2019 or Build Tools for Visual Studio
• git

Build steps

• Clone openvpn repo

  C:\Temp>git clone https://github.com/OpenVPN/openvpn.git
  

• Setup vcpkg

  C:\Temp>git clone https://github.com/microsoft/vcpkg.git
  ...
  C:\Temp>cd vcpkg
  C:\Temp\vcpkg>bootstrap-vcpkg.bat
  ...
  C:\Temp\vcpkg>vcpkg integrate install
  

• Install dependencies

  C:\Temp\vcpkg>vcpkg --overlay-ports=c:\Temp\openvpn\contrib\vcpkg-ports
                      --overlay-triplets=c:\Temp\openvpn\contrib\vcpkg-triplets
                      --triplet=x64-windows-ovpn
                      install openssl3 lz4 lzo pkcs11-helper tap-windows6
  

• Build openvpn

Now you could just open solution file openvpn.sln in Visual Studio and build from there, or build from VS Developer Command Prompt:

c:\Temp\openvpn>msbuild /p:Configuration=Release /p:Platform=x64

Supported platforms are x64, ARM64 and Win32. Remember to install dependency for specific platform before building openvpn.