How to sort products by brand?

Question

opencart

Hello. On the website echo-nvrsk.ru, it is necessary that in some categories, products of the same brand (KaVo) be in the first places when sorting by default.
In 2 categories "Equipment for the clinic - Microscopes" and "Equipment for the doctor" it turned out to be easy to specify the sorting order for the goods 1,2,3, etc. and they are by default in the first places.
In the category "Equipment equipment" 9 products of this brand. Gave them a sort order of 1,2,3, etc. - but nothing has changed.
Is it correct that if you only specify the order 1,2,3 for these products and the order 0 for the rest, then they should be displayed? Or everyone else should also specify. Or how can it be done in the least amount of time?