The “Brown” trail is on the other side of the hill. Cross over the road and head up the forestry track (its not directly opposite the entrance to wolftrax, a bit towards the A9 direction) and follow the forestry road. After about 1km there is a hairpin to the right and then it heads reasonably steeply up. Follow this, as you head back into the trees the track stops and there is a singletrack off to the left that goes up very steep, more of a push. Follow this and you can see one trail go off to the right or you can carry on and there is another one.
We did this just by having a look and strava and exploring, its all pretty obvious once you are up there!
Also i was there about 10 days ago, the lower red is closed, but we rode it from the start to Ayres Rock and then rejoined the forestry track climb there just to break the climb up slightly.