Webcc depends on `std::filesystem` which is a C++17 feature. There's a branch ([legacy](https://github.com/sprinfall/webcc/tree/legacy)) which is still using `boost::filesystem` so it could be built with VS2013. Check out it if you have only VS2013.
During the installation, you will be asked to copy OpenSSL DLLs (`libcrypto-1_1-x64.dll` and `libssl-1_1-x64.dll`) to "The Windows system directory" or "The OpenSSL libraries (/bin) directory". If you choose the later, remember to add the path (e.g., `C:\Program Files\OpenSSL-Win64\bin`) to the `PATH` environment variable.
OpenSSL can also be statically linked (see `C:\Program Files\OpenSSL-Win64\lib\VC\static`), but it's not recommended. Because the static libraries might not match the version of your VS.
The `CMAKE_INSTALL_PREFIX` has been changed to `D:/lib/cmake_install_2019_64` (NOTE: use "/" instead of "\\" as path seperators!). This path should be added to an environment variable named `CMAKE_PREFIX_PATH`. Then, CMake can find this installed Googletest during the configuration of Webcc.
Open CMake, set **Where is the source code** to Webcc root directory (e.g., `D:/github/webcc`), set **Where to build the binaries** to any directory (e.g., `D:/github/webcc/build_2019_64`).
In the center of CMake, you can see a lot of configure options which are grouped. Change them according to your need. E.g., set `WEBCC_ENABLE_SSL` to `1` to enable OpenSSL.

Click _**Configure**_ button again. OpenSSL should be found.