The best way to get started with understanding HBase is through the HBase shell.
On any cluster where the HBase client or server is installed, type hbase shell to get a prompt into HBase:
hbase(main):004:0> version1.1.2.2.3.6.2-3, r2873b074585fce900c3f9592ae16fdd2d4d3a446, Thu Aug 4 18:41:44 UTC 2016
This tells you the version of HBase that is running on the cluster. In this instance, the HBase version is ...