I went to the Jekyll website https://jekyllrb.com/docs/installation/ and read the pre-requisites
I ran each command line recommended to validate the correct prerequisites are installed
Installing Jekyll should be straight-forward if all requirements are met. Before you start, make sure your system has the following: GNU/Linux, Unix, or macOS Ruby version 2.2.5 or above, including all development headers (ruby installation can be checked by running ruby -v, development headers can be checked on Ubuntu by running apt list --installed ruby-dev) RubyGems (which you can check by running gem -v) GCC and Make (in case your system doesn't have them installed, which you can check by running gcc -v,g++ -v and make -v in your system's command line interface)