I have 2 Models, Cars & Brands
When I want to create new car and set values everything works like
$car->setYear('2015'); // setYear on $car
$car->setNote('This car has electric problems'); // setNote on $car
$car->setBrand(\Salon\Models\Brand = $_['brand_id']);
I think you should understand the SOLID principles first, to be able to solve these kinds of problems.
You can take a look at S.O.L.I.D specially the Interface Segregation Principle