Can you elaborate a bit more on what you are trying to do?

I am attempting to utilize the TAB feature which was available in previous versions. It allows me to open a new web site in a tab and not a new window. I do not see it in the pull down menu, websites say it can be enabled by clicking on the cogwheel in upper right corner, I do not have a cogwheel. Thank you in advance for any assistance.

The only "cogwheel" that have seen is for changing the configuration of the New Tab page = about:newtab typed in the Address Bar to load it.

No relationship to opening a new web site in a tab and not a new window.

That is in Options > General --> Tabs = Open new windows in a new tab instead

Hi buffbill, you can check the main application menu for Options if you don't have a toolbar button for it. That's the menu you open using the button at the right end of the main toolbar, with the 3 horizontal bars.

Please also see this thread for some fine-tuning you can do to the feature: https://support.mozilla.org/questions/1193456