The default installer copy/paste a skeleton for a website colored with tailwindcss.
To update it juste go in ./assets and edit app.js, app.css, directly the tailwind configuration or the webpack.config.js.
Then run wepback :
yarn && yarn encore (dev|production)
If you want to change the default location for assets, just edit ./config/packages/pushword.yaml and configure apps.0.assets (eg)