I'm currently learning PyGObject in order to create a small Gtk application, and I've become a bit stuck in laying out the Gtk Widgets correctly in the application window. The desired layout I am trying to achieve is below:

+-------+
| Label |
+-------+---+
| Combo Box |
+-----------+--------+
| Label     | Button |
+-----------+--------+
| Button             |  |
+--------------------+   > Dialog window of buttons of dynamic length
| Button             |  |
+--------------------+  |
| Button             |  |
+--------------------+  |
...

I have read the documentation on layout containers here, https://python-gtk-3-tutorial.readthedocs.io/en/latest/layout.html, but I'm having difficulty finding how I can set the properties of the Gtk Grid to resemble the above layout. I would appreciate it if someone could point me in the right direction here. Should I be using a Gtk Grid for this, or some other layout? Do I need to write up an XML file to set this layout, or is it possible to do something like this in the code?