There are three ways that you can do in order to get Bitcoins in your wallet:

Mining

With super computers, you are able to mine your own Bitcoins. With every math puzzle you solve to process a Bitcoin transaction, you will be automatically rewarded with Bitcoins by the system. For further information regarding mining Bitcoin, please see here

Pasar Bitcoin (Trade Exchange)

There are hundreds of online Bitcoin exchanges where you can buy Bitcoin with any currency in the world, such as USD, EUR, or even IDR. To buy Bitcoin with Rupiah, visit the biggest Bitcoin exchange in Indonesia: Indodax.com

Faucet

There are several websites that can give you Bitcoins for free by doing small requirements such as clicking ads, watching videos, playing games, etc.