When using flask-login for authentication, here's the general workflow:

• install flask-login and flask-bcrypt
• create a LoginManager instance and add the app and login view (the name of the template you're using for login)
• define a user model inheriting from UserMixin (required for some default implementations of authentication methods)
• define a function for loading users (remember to include the user_loader decorator from your login manager)
• use the login_user function to log the user in (after ensuring that the user exists and the passwords match)
• bcrypt can be implemented using flask-bcrypt (see generate_password_hash and check_password_hash)
• use the @login_required decorator to require authentication for controller functions
• flask-login gives you some methods for checking a user's properties (whether it's an anonymous user, or if the user is authenticated)

For more info, see the documentation for flask-login here.