How do I import a jupyter notebook? or open?

In the directory where the file you want to open is located on the command line, type: jupyter notebook , and then you have a new service "listening" on port 8888, see:

$ jupyter notebook
[I 10:51:49.289 NotebookApp] Serving notebooks from local directory: /home/sidon
[I 10:51:49.290 NotebookApp] 0 active kernels 
[I 10:51:49.290 NotebookApp] The Jupyter Notebook is running at: http://localhost:8888/?token=b7808c09d59aee2e93462fb522a71faab25eff1294882789
[I 10:51:49.290 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 10:51:49.290 NotebookApp] 

    Copy/paste this URL into your browser when you connect for the first time,
    to login with a token:
        http://localhost:8888/?token=b7808c09d59aee2e93462fb522a71faab25eff1294882789
[I 10:51:49.920 NotebookApp] Accepting one-time-token-authenticated connection from ::1
[W 10:51:50.563 NotebookApp] 404 GET /api/kernels/7977e2c8-73bf-4713-81ce-125211de1f82/channels?session_id=DA68001D28A447BF9F79B9315E67F6FA (::1): Kernel does not exist: 7977e2c8-73bf-4713-81ce-125211de1f82
[W 10:51:50.598 NotebookApp] 404 GET /api/kernels/7977e2c8-73bf-4713-81ce-125211de1f82/channels?session_id=DA68001D28A447BF9F79B9315E67F6FA (::1) 60.22ms referer=None
[W 10:51:58.606 NotebookApp] Replacing stale connection: 7977e2c8-73bf-4713-81ce-125211de1f82:DA68001D28A447BF9F79B9315E67F6FA

As the output of the command says, now you just need to go to a browser and access the address: http://localhost:8888/?token=b7808c09d59aee2e93462fb522a71faab25eff1294882789 (The token is only for the first time), then you will see all the files in the directory, just double click on the file you want to open.

To install jupyter, see this link.

I was trying to import from the command line and it's not working! but I already gave it up, and I imported it the traditional way by pressing the add file button.