The way workspaces work currently on Gnome Shell is unified and communicating. If you open an application on one workspace, you will find the icon on the dock of all workspaces, and if you press it you are thrown automatically to the workspace that the application is opened.
The workspace seperation on dash extension allows you to handle every workspace as if it was the only one. You won’t find opened applications of workspace 1 appearing on the dock of workspace 2 and if you open the same application on two workspaces it will launch independently again instead of pointing you to the already opened window.
To install this extension, simply turn the switch to “ON”