Link Python script to HTML form

Ok I have checked some of the related questions and can't seem to find the exact one.

Basically I have pretty much hard-coded a website, there's a tiny bit of use of bootstrap.

I wanted to code a contact form, I've started to learn Python and therefore used Flask to code one.

Right now the form is separate to all of the html files because I coded a separate project.

I know that I could create a full Flask project and redefine all of my html files through the app and have the app generate URL's for it, but that would be a hell of a lot of work at this point for the sake of a contact form.

Is there any way that I can define the form in HTML and have it refer to the Python Flask script?

I have literally no idea how to do this and I can't find an answer anywhere on Google but then I might be searching the wrong thing.

So, here's my HTML:

   <form action="routes.py" method="post" class="basic-grey">
         <label>
            <span>Your Name :</span>
             <input id="name" type="text" name="name" placeholder="Your Full Name" />
         </label>

         <label>
             <span>Your Email :</span>
             <input id="email" type="email" name="email" placeholder="Valid Email Address" />
         </label>

         <label>
             <span>Message :</span>
             <textarea id="message" name="message" placeholder="Your  Message to Us"></textarea>
         </label>     
          <label>
             <span>&nbsp;</span> 
             <input type="button" class="button" value="Send" /> 
         </label>    
    </form>

And here is the Python Flask Script:

# Imported the Flask class and a function render_template
from flask import Flask, render_template, request, flash
from forms import ContactForm
from flask.ext.mail import Message, Mail
import os

mail = Mail()

# Created an instance/object of the Flask class
app = Flask(__name__)

app.secret_key = os.urandom(24)

# Mapped the URL '/' to the function home().
# Now when someone visits this URL, the function home() will execute.
# This uses a decorator to tell Flask which URL will cause the function below  it to execute.

app.config['MAIL_SERVER']='smtp.gmail.com'
app.config['MAIL_PORT'] = 465
app.config['MAIL_USERNAME'] = 'fernindustrials@gmail.com'
app.config['MAIL_PASSWORD'] = 'l3d23pp3l1n'
app.config['MAIL_USE_TLS'] = False
app.config['MAIL_USE_SSL'] = True

mail.init_app(app)

@app.route('/contact', methods=['GET','POST'])
def contact():
form = ContactForm()

if request.method == 'POST':
    if form.validate() == False:
        flash('All fields are required.')
        return render_template('contact.html', form=form)
    else:
        msg = Message(form.subject.data, sender='contact@example.com')
        msg.recipients = ["fernindustrials@gmail.com"]
        msg.body="""
        From: %s <%s>
        %s
        """ % (form.name.data, form.email.data,  form.message.data)
        mail.send(msg)

        return render_template('posted.html')

elif request.method == 'GET':
    return render_template('contact.html', form=form)

# Use run() to run our app on a local server.
if __name__ == '__main__':
app.run(debug = True)

In order to not breach the rules I wont post the Forms.py file that I have unless someone needs that to.

Is there anything I need to change or do differently? Is it even possible?

Also where does the script go in reference to the index.html files, i.e what is the project structure?