Please see the either the [online documentation](https://docs.corda.net/running-the-demos.html#attachment-demo) for more info on the attachment demo, or the [included offline version](../../docs/build/html/running-the-demos.html#attachment-demo).
From the root directory of the repository, run the following commands (on mac / unix, replace `gradle` with `./gradlew`)
gradle samples:attachment-demo:deployNodes
./samples/attachment-demo/build/nodes/runnodes
gradle samples:attachment-demo:runRecipient # (in one window)
gradle samples:attachment-demo:runSender # (in another window)