Click the extension's toolbar button to pop out selected tab(s) to a new window.
Default shortcut: Alt+P.
Usually you have just the current tab selected, but Chrome also has built-in functionality to select multiple tabs:
— To select specific tabs in a window, click tab handles while holding down Cmd (Mac) or Ctrl (Windows) key.
— To select a range of tabs, click tab handles while holding down the Shift key.
Source code: https://github.com/ivan7237d/pop-out-tabs