To build your own app using Hyperledger Fabric, you need to first understand the complete concept of Hyperledger Fabric. To understand the Hyperledger Fabric concept complete, you can go through the Hyperledger Fabric Documentation available here:http://hyperledger-fabric.readthedocs.io/en/release/blockchain.html
After understanding the concept, you can get started with building your app. To start building, you first need to setup a development environment: http://hyperledger-fabric.readthedocs.io/en/release/getting_started.html
Next, build your first network
Finally, build your first application
After you do all this, you’ll get an idea of how to build your own app.