I installed Nbextensions on jupyternotebook, but no tabs appear on the menu.

I use anaconda, jupyternotebook.
I installed nbextension because it seems convenient.
(I downloaded it and put it in the current folder.)
If you look at the anaconda navigator, you can see
as shown in the image below. Appears in the list of installed

However, the Nbextensions tab does not appear on the main screen of the jupyternotebook.

How can I see it?

Is it not installed properly?

<Additional note: October 24, 2018>
This is not the point of this question, but recently when I used the jupyter notebook, I typed "jupyter notebook" from the terminal and started it, so I didn't notice it.
I checked the condition that jupyter notebook is no longer started from the anaconda navigator tab.Is there any competition?Do you want to try reinstalling anaconda navigator?
When you click on the tab, the green barometer for progress starts to move, but then the browser does not start.I used to stand up normally from the Anaconda tab.