according to the documentation, installation for tcWebhooks is as follows
Download the jar file. Locate the plugins directory for your TeamCity install. This is normally $HOME/.BuildServer/plugins/. Create a new directory (folder) inside the plugins directory called "tcWebHooks" (it can be named whatever you want). Copy the jar you downloaded into the tcWebHooks directory. Restart TeamCity.
TeamCity Professional 7.1.4 (build 24331) didn't create a .BuildServer folder and I cannot find that anywhere on my machine. Does anyone know the default path for the installation of plugins? I see there is a plugins folder at "C:\TeamCity\buildAgent\plugins" which contains a lot of plugins but following the above instructions still doesn't seem to pick up the plugin.