I want to know, how can i achieve this in Qlik Sense.
When I clicked on button A - it shows me graph 1,2. when i click on button 2 - it shows me graph 3, 4 and hide graph 1 ,2.
There is no implicit option available to achieve this yet. But you can develop this by building an extension object. The scenario which you have mentioned is totally possible in QlikSense with extension objects.
Look at qlikbranch or here
qWidget | Getting Started - Basics
Retrieving data ...