Follow instructions for setting up OpenSSL. For Ubuntu users, the following command works.
sudo apt-get install pkg-config libssl-dev
Use following instructions to install the protobuf compiler on Ubuntu or similar Linux platforms.
$ wget https://github.com/protocolbuffers/protobuf/releases/download/v3.11.4/protobuf-all-3.11.4.tar.gz
$ tar xzf protobuf-all-3.11.4.tar.gz
$ cd protobuf-3.11.4
$ ./configure
$ make
$ sudo make install
$ sudo ldconfig
MacOS user can install with brew
$ brew install protobuf