Update manifest file with proper license key as described above in root README file.
HERE Mobile SDK provides feature to navigate inside Venues. Current snippet of code will gives you a basic idea how to utilize this feature in your application.
For testing purposes you may use Alexa Shopping Mall (Venue ID: DM_7171). Enter the value in text field and tap "OPEN" button. After Venue is open you can navigate inside. To build route tap "ROUTING", then tap "Start location" and pick start position, tap on "End location" and choose end position. Finally tap "SHOW ROUTE" and you will see the route on a screen.
Look at code and SDK API Documentation to get more details.
To find more venues use search features in SDK and check sample search app.