How to bind objects created in a Django form?

Question

JavaScript

2 forms Objects and Apartments are displayed on the page. How to create and set a link by key when submitting completed forms. Or how to reshape.
In the future, the shape of the Object will be combined with other shapes.

views.py

def add_flat(request):
    if request.method=='POST':
        objform=ObjForm(request.POST)
        flatform=FlatForm(request.POST)
        #print(objform)
        if flatform.is_valid() and objform.is_valid():
            #print(objform.cleaned_data)
            #flat=flatform.save()
            #obj=objform.save(commit=False)
            #obj.foreignkeytoA=flat # не работает 
            #obj.save()
            return redirect('obj')
    else:
        objform=ObjForm(initial={'real':1})
        flatform=FlatForm()
    return render (request, "firstapp/addflat.html", {'objform':objform , 'flatform':flatform})

forms.py

class ObjForm (forms.ModelForm):
    class Meta:
        model=Obj
        fields=('real','d_type','r_type','s_type','coast','agent','client','region','district','location','street','apartment','source','comments')
        widgets={
            'real': forms.Select(attrs={'class':'form-select'}), #,'disabled':'disabled'
            'd_type':forms.Select(attrs={'class':'form-select'}),
            'r_type':forms.Select(attrs={'class':'form-select'}),
            's_type':forms.Select(attrs={'class':'form-select'}),
            'coast':forms.NumberInput(attrs={"class":"form-control"}),
            'agent': forms.Select(attrs={'class':'form-select'}),
            'client':forms.Select(attrs={'class':'form-select'}),
            'region':forms.TextInput(attrs={"class":"form-control"}),
            'district':forms.TextInput(attrs={"class":"form-control"}),
            'location':forms.TextInput(attrs={"class":"form-control"}),
            'street':forms.TextInput(attrs={"class":"form-control"}),
            'apartment':forms.TextInput(attrs={"class":"form-control"}),
            'source':forms.Select(attrs={'class':'form-select'}),
            'comments':forms.Textarea(attrs={"class":"form-control"}),
        }
        #exclude = ('real',)
        
class FlatForm (forms.ModelForm):
    class Meta:
        model=Flat
        fields='__all__'
        widgets={
            'room_c':forms.NumberInput(attrs={'class':'form-control'}),
            'floor':forms.NumberInput(attrs={'class':'form-control'}),
        }

models.py

class Flat(models.Model):
   
    re_id=models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    room_c=models.PositiveSmallIntegerField(verbose_name="Кол-во комнат")
    floor=models.PositiveSmallIntegerField(verbose_name="Этаж")
    

class Home(models.Model):
    
    re_id=models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    home_area=models.PositiveSmallIntegerField(verbose_name="Площадь дома")
    floors=models.PositiveSmallIntegerField(verbose_name="Этажей в доме")

class Obj(models.Model):
    agent=models.ForeignKey(Agent, verbose_name="Агент", on_delete=models.DO_NOTHING)
    client=models.ForeignKey(Client, verbose_name="Клиент", on_delete=models.DO_NOTHING)

    d_type_ch=( #тип сделки 
        ('sale','Продажа'),
        ('rent','Аренда'),
    )

    r_type_ch=( #тип родажи или аренды
        ('day','Посуточно'),
        ('months','Помесячно'),
        ('long','Долгосрочная'),   
    )

    s_type_ch=(
        ('direct','Прямая'),
        ('alter','Альтернатива'),
    )
    
    source_ch=( #Источник лида
        (1,'Входяший звонок'),
        (2,'Исходящий звонок'),
        (3,'Наш сайт'),
        (4,'Сторонний сайт'),
        (5,'По знакомству'),
        (6,'Самостоятельный поиск'),
    )

    real_ch=( #тип недвижимости
        (1,'Квартира'),
        (2,'Дом'),
        (3,'Земельный участок'),
        (4,'Коммерч'),
        (5,'Гараж'),
    )
    real=models.PositiveSmallIntegerField(choices=real_ch,verbose_name="Тип недвижимости")

    region=models.CharField(max_length=40,verbose_name="Регион")
    district=models.CharField(max_length=60,verbose_name="Район") #район\округ
    location=models.CharField(max_length=60,verbose_name="Населенный пункт") # населенный пункт
    street=models.CharField(max_length=60,verbose_name="Улица") 
    apartment=models.CharField(max_length=10,verbose_name="Дом")

    comments=models.TextField(verbose_name="Служебный комментарий") #Служебный комментарий

    #cadastral_number=models.CharField(max_length=10, null=True, blank=True) #Кадастровый номер
    coast=models.PositiveIntegerField(verbose_name="Начальная стоимость") #Стоимость 0=min 1=max

    source=models.PositiveSmallIntegerField(choices=source_ch,null=True, blank=True,verbose_name="Источник") #источник
    d_type=models.CharField(max_length=20, choices=d_type_ch,verbose_name="Тип сделки") #тип родажа или аренда
    r_type=models.CharField(max_length=20,null=True, blank=True, choices=r_type_ch,verbose_name="Тип аренды") #тип Аренды
    s_type=models.CharField(max_length=20,null=True, blank=True, choices=s_type_ch,verbose_name="Тип продажи") #тип Продажи

    Flat=models.ForeignKey(Flat,null=True, blank=True, verbose_name="Квартира", on_delete=models.DO_NOTHING)
    Home=models.ForeignKey(Home, null=True,blank=True, verbose_name="Дом", on_delete=models.DO_NOTHING)

Answer 1

Found an error
removed return false;

Answer 2

I found it difficult to understand your question because the code examples contain a lot of details that are not relevant to the problem. Try creating a minimal reproducible example next time .
Essentially, your actions should be something like this:

if flatform.is_valid() and objform.is_valid():
    with transaction.atomic()
        flat = flatform.save()
        obj = objform.save(commit=False)
        obj.Flat = flat
        obj.save()