To move an extension from one group to another, locate it the Directory, click on it and and drag it across towards the Extension groups panel. Whilst still holding down your left mouse button, position the mouse pointer on top of the group you want to move the extension into, until it is highlighted. Release the mouse button to drop the extension into this group. The focus will be remaining with the group from which the extension was moved, to assist you when moving more than one extension.
To move another extension, follow the same procedure. Click on the group you have moved the extension into and this should be displayed in the Extensions list panel. Click on the button to apply the new configuration.
In the example below, extension 208 was moved from the New Extensions group to the Accounts group.