The easiest way is to first create a BT instance in the Cloud Console on the website and then connect to it in Java by specifying the ProjectID and the Instance ID:
Connection = BigtableConfiguration.connect(PROJECT_ID, INSTANCE_ID);
PROJECT_ID
is your Cloud project (make sure to use the actual project ID rather than the alias) and INSTANCE_ID
is the name you gave to your BT instance via the website.
The page to create the BT instance is within the menu at the top-left of the Cloud Console page.
Some personal observations:
1 Your instance is billed hourly, so don't forget to delete it when done (YOUR DATA WILL BE DELETED)
2 You will be charged for each hour that it's on (i.e. even if you keep it for 5 min, you will be charged for the full hour)
3 Create the Connection object once and re-use it.
4 When creating an instance, specify the region where your client is, to avoid network charges
5 Don't expect all HBase API and functionality to fully work in Bigtable, but most of it does