If you start with your first application with Hedera Hashgraph, the easiest way is to download the SDK from the homepage and copy and start modifying one of the existing applications. For this:
1. Download the project from : https://www.swirlds.com/download/
2. Copy one of the applications under sdk/source
3. Rename the folder and rename the name references in the pom.xml file.
4. Open Eclipse
5. Import the files as a "Maven" project
6. Rename the Main and State java files, objects and all the references to the name of your projects
7. Press "Run As" as "Maven Install" to get the binaries.
8. Configure your application in the config.txt file.
9. Start and test your application with swirlds.