Probably the best way to get started is to just clone this repository and check out the example application.
There's also some documentation in form of a Maven site, though the site is not published and you have to build it yourself running:
mvn site
The generated site index is located in REPO_ROOT/target/site/index.html.
Releases are not published to Maven Central, however builds are available from this Maven repository:
https://java.panter.ch/nexus/content/repositories/oss-releases/
Add this repository to your projects pom.xml using a repositories-section:
<repositories>
<repository>
<id>vaadin-mvp-releases</id>
<url>https://java.panter.ch/nexus/content/repositories/oss-releases/</url>
</repository>
</repositories>
If you're using a repository manager (Nexus, Archiva, ...) then add this repository to its configuration.