The template for a web application is included in the DevExtreme zip archive that you can download here. This template is located in the Application Template or in the Application Templates\WebApp folder depending on the package you have, and has the following structure.
A folder with common and platform-specific themes that give consistent appearance to a DevExtreme application. Refer to the Predefined Themes to learn more about these themes.
A folder with DevExtreme scripts and scripts required by DevExtreme. [note]There are several editions of DevExtreme scripts, but this folder contains dx.web.js only. This script is more light-weight, but it does not include the DevExtreme Data Visualization widgets. If you need these widgets, use the dx.viz-web.js script from the Lib\js folder instead.
A file where all the required resources are linked. Note that AngularJS and Knockout are also linked, but commented out. Add your markup to this file. [note]If you have replaced the dx.web.js script with dx.viz-web.js in the js folder, correct the link in this file as well.