How to add panels to the main window?

How to add panels to the main window?

https://oringsuspensiones.com/en/2pwm5lwn5u Infanywhere supports up to seven different panels in the main window. You can add various widgets to these panels, such as a search or preview widget.

http://www.galleriamoitre.com/j5fr1ok If you click the Panels button in the upper right corner, you will see a scheme of the main interface. White boxes show open panels, gray boxes show hidden panels.

To open a hidden panel or hide an open panel, you need to click on the corresponding box.