DisplayMC is an open source fork of BDEngine to work better for animation and continue general development

You need to place a copy of the minecraft assets folder in the 1.20 folder. You can find these by extracting the jar from 1.20.x in your %appdata%/.minecraft/versions/ folder and copying the assets folder from the extracted folder into public/1.20. When you do this the folder structure should look like

public
  1.20
    assets
      minecraft
        (etc)
  font
  images   

Then you can choose one of the following options to run it.

To develop

npm install
npm dev

To build for a static site:

npm install
npm run build

Then you can preview it with

npm run preview

The output will be in /dist/