Examine the pattern of the tread - if there's some directionality it will be in the form of chevrons, whether solid shapes or an arrangement of separate blocks or grooves. For smooth running on a paved surface you want the tip of the chevron to make contact before the sides, so the chevrons should be pointing forwards as you look at the tyre from above. This "might" also displace surface water to the sides. It is the direction for the rear tyre on dirt to dig in under traction, increasing its contact area. Reverse that for the front, so it digs in under braking. There is an argument for reversing those directions in soft sand because if the tyre digs in you'll just bury the wheel without gaining traction. IMHO YMMV