How do I create a relation manager for a pivot table

// In Container model
public function transporters()
{
    return $this->belongsToMany(Transporter::class, 'container_transporter')
                ->withPivot('price');
}

// In Transporter model
public function containers()
{
    return $this->belongsToMany(Container::class, 'container_transporter')
                ->withPivot('price');
}