How do I get grid workspaces in ubuntu 20.04?

I know that I have to use some tweaking tool and then a extension for this. But all extensions that are suggested for this(Workspace grid, Workspace matrix), aren't available in the software center.

I use Workspace Matrix Gnome Extension and it works just perfectly and has some useful configuration settings.

On Ubuntu 20.04.2 LTS and Gnome 3.36.8, Firefox 90.0, follow these steps to enable it:

1. Navigate to https://extensions.gnome.org/ (tested with Firefox and Chrome)

2. Click "Click here to install browser extension" (e.g., in Chrome it's this plugin)

   

3. Search "Workspace Matrix" and enter its detail page

   

4. Turn on the extension by click top-right button

   

5. Navigate to extension settings by click to-right button of step 4, or search "extension" in the activities window, or click on "installed extensions" on top

   

Final effect:

That's all.