This tutorial assumes you have already

Follow the tutorial for your prefered IDE (I personally recommend IntelliJ for the reasons laid out in the Pre-requisites)

IntelliJ (Made for IntelliJ Community Edition 2019.3 (released November 28 2019))

IntelliJ Old (Made for IntelliJ Community Edition 2019.3.4 (released November 28 2019))

Eclipse (Made for Eclipse Photon (released June 2018))

VSCode

1.2 - Basic Mod