Hey Lim. Glad you're playing. Should've rolled on Hyperion though.
Don't bother with materia (edit: okay, it's worth it, but it shouldn't be your focus AT FIRST).
Ifrit Hard can be done in AF with a PUG. It's a joke. Just bring a good stunner (literally the only important thing in this fight).
Garuda Hard on the other hand has a major DPS check in Stage 2. You will need a set of DDs in at least 50% Darklight to consistently clear it due to the green tether's regen.
Admapor Keep has a DPS check on Demon Wall. You need some good gear to finish it off quickly. I would recommend doing DD > AV > WP and once you get a Darklight weapon, spam AK until you get a full set of AK gear with maybe 1-2 pieces of Darklight. Then you can begin your relic quest without being a detriment to the group (Hydra is no joke and Garuda requires good gear - let's not talk about Titan).