How do you write a save method for forms in django?

I have two models in Django: User (pre-defined by Django) and UserProfile. The two are connected via a foreign key. I'm creating a form that allows a customer to edit their user profile. As such, this form will be based on both models mentioned.

How do I create a save() method for this form? What are the steps/requirements in completing the save function?

Here's what I have so far in forms.py:

class UserChangeForm(forms.Form):
    #fields corresponding to User Model
    email = forms.EmailField(required=True)
    first_name = forms.CharField(max_length = 30)
    last_name = forms.CharField(max_length = 30)
    password1 = forms.CharField(max_length=30, widget=forms.PasswordInput)
    password2 = forms.CharField(max_length=30, widget=forms.PasswordInput)

    #fields corresponding to UserProfile Model
    gender = forms.CharField(max_length = 30, widget=forms.Select)
    year = forms.CharField(max_length = 30, widget=forms.Select)
    location = forms.CharField(max_length = 30, widget=forms.Select)

    class Meta:
        fields = ("username", "email", "password1", "password2", "location", "gender", "year", "first_name", "last_name")

    def save(self):
        data = self.cleaned_data
        # What to do next over here?

Is this a good start or would anyone recommend changing this up before we start writing the save() function?