The best advice that I can give you is to read your tooltips, and maybe focus on one job mechanic at a time. You basically need to learn:
1. How Kardia and Soteria work (which is mostly just set and forget for easy content).
2. How Eukrasia and Toxikon work.
3. The heals available through Addersgall/Rhizomata. (Compare these to lily heals, you don’t get something like afflatus misery, but you do recover MP when you use these so you want to use these often).
4. The cooldowns available to you (Physis, Haimas etc). (Compare these to asylum and lilybell).
5. DPSing is similar, but Dyskrasia is instant so you can heal between Dyskrasia casts easily. SGE has a DPS cooldown, Phlegma, compare these to Presence of Mind and Assize.
The names are hard to remember, but a lot of abilities share effects with SCH, so I just remember them as Sage’s Lustrate and Sage’s Soil. If you’ve never played SCH before, you can try to remember them by icons. To build muscle memory, you can do early dungeons where you only need to focus on some of the job mechanics.
Momo’s healer guides are usually great, this one is a little more beginner/intermediate focused:
https://youtu.be/UPjdwUgwncI?si=HGmTxO3zX7aXDKnN.