To change the virtual location on Betternet, it is needed to first sign in to your Premium Membership. Once you have signed in click on the US flag (location selected by default) which is under the Connect button, then you will be able to select from 80+ locations from all over the world, or the Optimal Location which would be the most convenient location depending on where you are located and the number of users connected to that server. 
NOTE: To have access to change Virtual Locations, it is needed to have a Premium Membership. Free accounts only have access to connect to the US without the option to select any of the locations within the US servers.