Compile OpenVPN or SoftEther as DLL for use in C # WPF

I am trying to make a front end for my friends a VPN Server hosting company. I have done most of the application with WPF and it works as a standalone product. It downloads the server list from its site using JSON and fills in the content of the selection, runs ping tests, etc.

Now I'm at the point where I need to get it to do something - my options seem to be OpenVPN or SoftEther.

I tried to create OpenVPN as they recommend with VS2010, and SoftEther since 2008 Professional. I'm really struggling to get a working build, either when their websites say it should only work if the dependencies are satisfied.

My understanding here is that I need to create a client from one of these two parameters as a dll, which I can then use as a lib in my C # application and call any public connection functions and pass the username and password entered into my graphical interface.

Am I on the right chain of thought? Has anyone out there successfully integrated OpenVPN or SoftEther into their own products?

I should mention that I completely lost OpenVPN, but SoftEther builds for the most part, but the installer is half empty and the drivers are not installed for the virtual adapter either. Of course, I can install them using the prebuilt binaries on the respective sites.