How to get adjacent values ​​stored in the database in Django?

Question

Django

Hello, dear forum users. Please help me figure it out.

How to get the values ​​of several fields from the model connected via ForeignKey in the "views.py" file?

For example, let's take 2 models with parameters:

class Box(models.Model):
    name = models.CharField(max_length=100)
    length = models.PositiveSmallIntegerField()
    width = models.PositiveSmallIntegerField()
    height = models.PositiveSmallIntegerField()
    
    def __str__(self):
        return str(self.name)

class Material(models.Model):
    name = models.CharField(max_length=100)
    price = models.FloatField()
    density = models.FloatField()
    
    def __str__(self):
        return str(self.name)

And the object model:

class Product(models.Model):
    box = models.ForeignKey(Box, on_delete=models.CASCADE)
    material = models.ForeignKey(Material, on_delete=models.CASCADE)
    
    def __str__(self):
        return str(self.box)

How can Django calculate cost, volume, or other parameters?
How to get the values ​​written in "Box.length", "Box.width", "Box.height" corresponding to the selected "Box.name" in views.py?