VAT refund non eu visitor at Brussels airport

Can anyone advise the most practical way for VAT refund at Brussels Airport?
Does the shopping have to be in one of shops with duty free logo, in the city? Which is the best shop for one stop shopping?? INNO Rue neuve?
And do they give cash in the refund booth?

I thought that they gave vat back in cash at the douane post in airport

I read a lot but am lost in the administrative procedure. My parents want to buy some electonics, cosmetics and household items but I can not advise them what the best solution is.