If you want to try this on your end the installation of the entire process is like this:
1) Installing Ionic 4:
a) First we need node.js - install it here https://nodejs.org/dist/v12.14.1/node-v12.14.1-x64.msi (note: clicking this link will automatically download the node installer).
b) Second lets install ionic cordova:
To install Cordova and Ionic, use - npm install -g cordova ionic .
c) Make sure to install the latest version of JDK (Java Development Kit)