Once, you are there, you'll see a forest entry door...from here it is a single dirt road in forest. Keep looking around you, you may find the herd. And carry a DSLR with you with large optical lens. Blackbucks are very alert animals, so if they see you before you do, than they will start running from you.. and trust me you don't wanna chase them. So, if you see them...go very quietly towards them using bushes as obstacles and if you see all looking at you...stand still or crouch on ground. They will loose interest in you if you don't move. I was lucky! as I found one raised landscape ahead of me and I used that it as cover. See, below how I crouched on ground to take shot..!