The projects in this directory are samples that integrate the @arcgis/core build of the ArcGIS API for JavaScript with various frameworks, module bundlers and build tools.
For additional information, see the Build with ES modules Guide topic in the SDK.
Step 1 - Run npm install.
Step 2 Configure CSS. Here's a React example:
index.js
@import "https://js.arcgis.com/4.19/@arcgis/core/assets/esri/themes/light/main.css";