Carbon filter: should I be pushing air through or pulling air through?

I am starting my first indoor grow and am a bit confused on what the best way for me to set up my carbon filter is... I have seen people set up their fan so it they are drawing air from the tent and pushing it through the filter. But have also seen people people put the carbon filter first and pull air through it. Which is the best way to keep smell down?

pulling

They are designed with an outer filter cover for pulling air into the filter and through it
But In a pinch I have used them in reverse and had them still absorb the smell

welcome to RIU. pulling as @Werp said is what you want - good luck with your grow

Pulling and don’t buy a cheap one it won’t be up to the job I thaught it was impossible to rid the smell until I brought my phresh one now not a single smell