Saurfang is a tank and spank affair for melee DPS. Just stand behind him and DPS away.
All of his skills and abilities need not be your concern. Yes, even the dreaded mark. They’re things that your healers have to address.
What you have to watch out for is what not to do when the adds spawn, and that involves not AoEing (see how I just turned that into a verb? You get it, right?). Since Fan of Knives has no place in the fight I doubt that you’ll be casting that and hitting the Blood Beasts by accident. Time Killing Spree and Blade Flurry carefully so that you’re only hitting the boss when they’re up.
2 Blood Beasts spawn on 10-man while 5 appear on 25. They don’t do much damage and therefore don’t need to be tanked, but when they hit a raid member they return blood points to Saurfang. This is the reason why they’re usually assigned to ranged DPS. If your raid leader wants you to help DPS them down, then hit hard and fast. Bring them down quickly so that they die before you get aggro.
I’m probably over-simplifying the fight at this point since the boss has more abilities than I mentioned here, but none of them should be of any concern to you as melee DPS.