Would like to PvM, but I fail miserably. Tips?

So obviously as the title states I would like to start bossing, and that be how I generate gold. Unfortunately I must be doing everything wrong because I get wrecked. For example I looked up some bosses that are "easy" to solo. Helwyr was what I settled on as a good starter boss. For context, my stats, 93 Str, 97 HP, 94 Att, 85 Def, 94 Mage, 99 Range, 88 Prayer (I currently am using curses), 1 Necro (haven't started yet). Now I know necro is OP but Helwyr it isn't needed either and will be leveling that soon. For the fight I was using Subjugation robes, virus wand, abysmal orb, fury (t), ring of fortune. I'm a fairly broke player so this is the gear I have.

Fight starts, I'm overloaded, shield ready for swap. I move from the poison, killing the wolves, and I'm getting destroyed. Had to emergency telly to avoid death. I know the gear isn't the best, but I feel like with my stats and that gear I should easily be able to do a couple kills. Any tips would be greatly appreciated.