Running Protobuild.exe on Mac & ldquo; Order not found & rdquo; Problem in terminal

I'm trying to build the development branch for Monogame and it instructs you to execute "mono Protobuild.exe" to create the solution files. I downloaded the github branch and in the terminal navigated to the file that the Protobuild.exe exists and then ran the command, but was given "command not found" when executed. Does anyone know what I am doing incorrectly here?

I have downloaded the Mono SDK.

FYI I found out that before you install Mono, you need to create the directory usr/local/bin in order for the terminal to detect the "mono" command.