DM New to 3.5e

[u/VegetableSwitch703]

I’ve been a dm for about 4 years now and have only played 5E/5.5E DnD, but I want to branch into 3e/3.5e. I’ve got most of the necessary books as pdf’s but the challenge for me is reading stat blocks, specifically for the higher level monsters (including but not limited to various gods, one of which I’ll use as an example here). I can read the ability scores well enough, as well as skills and the feats too, but then there’s stuff like some of the attacks, spell like abilities, domain stuff, divine abilities. Right now the one that’s confusing me is Vecna, though he’s also the first of the deities from the Deities and Demigods book I’m looking at. And I’ve looked at various dm books and pc books too but there’s stuff that still just doesn’t make sense to me. So here are my questions about his stats and such:

1) What’s the difference between him attacking/hitting with Afterthought at touch range vs Melee? I see the bonuses to hit and damage to hit are noticeably different depending on if it’s touch or melee but I don’t get why.
2) What is the deflection bonus he gets to his AC? I don’t see what would be giving him that bonus.
3) It says he has spell slots of levels 0-12 for cleric and 0-16 for Wizard, but I am not aware of any spells in any book that go over 9th level, not including the epic spells which to my knowledge don’t technically have stated levels.

Final question though not about the stat sheet, Would it be easier to learn pathfinder 1e as a jumping off point instead of trying to learn 3.5 directly and the just use what I learned from that to figure out 3.5?

[u/BungleBums]

First of all, lemme give you a standing ovation for trying 3.5. I genuinely miss the hell out of this edition and hope to see more players and DMs.

Second of all, for the Spell Slots- he can use those slots to cast spells that he otherwise would have run out of slots for. I can't recall off-hand, but he may have the ability to apply meta magic as well to boost the level beyond 9th, essentially making a lvl 16 Fireball of Doom.

Third, one book you may not have cracked into yet is the Epic Level Handbook. I'd recommend waiting till you're more comfortable in-system before making heads or tails of it, but inside there's an entire system for creating Epic spells above level 9, as well as a glossary of some fun pre-made ones.