The Marketplace Wizard will ask you for the features to install:
By default, only the required Reactive Blocks base feature is selected. It allows you to build code on Java SE. In case you already know that you want to develop for OSGi or Eclipse Kura, select these features as well. If you are not sure, just install the required base feature.
If the installation via the marketplace fails, you can try to install via the update site.
That’s it. Welcome to the Reactive Blocks world!