Beside the files and snippets tab on the top left side of the page there is supposed to be a css designer tab which does not appear for me
Thanks for writing to us. You can try resetting the current workspace by following the below steps.
The above will reset the workspace to default. Please confirm if the above worked for you else we will further debug the issue.
In the program's main menu, across the top, go to Window > CSS Designer or hit Shift + F11 to open the CSS Designer window.
You can then click and drag the named tab of the window to the edges of your application frame (next to or between other tool panels). When a highlight appears, release the tab to lock it in place.
Take a look at Rearranging Panels in Dreamweaver on this page for more info:https://helpx.adobe.com/il_en/dreamweaver/using/dreamweaver-workflow-workspace.html.
Use Shift + F11 to open CSS Designer panel. Or access it from the Window menu.
Personally, I never use the designer panel. DW's code hints and auto code completion are much faster and less tedious than panels.