To run the flask app, open the command prompt and navigate to the folder that holds the full application. Ensure that you have virtualenv installed on your computer using these instructions.
In the command line, enter the following code to activate the virtual environment:
$ venv\scripts\activate
If you're using a Mac, you'll need to use the following code:
$ venv/bin/activate
Now, enter the following code to run the flask app:
$ set FLASK_APP=main.py
$ flask run
* Running on http://127.0.0.1:5000/
If you are using a Mac or Linux, you'll need to use 'export' instead of 'set'
Now, just head over to http://127.0.0.1:5000/ to view the running application.