I just cant grasp Sage

[AnotherPerson]

If you're really struggling, I recommend to go practice in a lower level dungeon first so it's not as if you get a full list of skills you have to figure out. This helps you consolidate a small section of the sage's toolkit at a time. After familiarizing with what you have learned so far, then you can go read tooltips for other skills, and then practice those skills in a higher level dungeon. That helped me get a good grasp of the Sage's toolkit.

EX: If you pop Kradia on the tank in Satasha and then spam Dosis, you can sustain them very well at Satasha (Lv 15).
Then you go to level 30 dungeons to practice how Eukrasia works and Phlegma for positioning.
Then you go to level 45 to 50 dungeons to practice with your Sage Gauge, Icarus, and Soteria. At this point, you should be working on getting a feel on when to heal, and how much you can use your passive healing from Kardia to sustain them.
Then to level 60 for new abilities - practicing how Zoe will augment your heals, when to best use Pepsis over your other healing tools, and how effective the upgraded Physis II works in tandem to your healing abilities.
Then to level 70 for newer abilities - figuring out when to use Taurochole and Haima, preshielding for Toxikon stacks.
And then you're set to where you need to be. You can continue the same pattern of learning at level 80 and level 90.

[Maxilor]

If you're really struggling, I recommend to go practice in a lower level dungeon first so it's not as if you get a full list of skills you have to figure out. This helps you consolidate a small section of the sage's toolkit at a time. After familiarizing with what you have learned so far, then you can go read tooltips for other skills, and then practice those skills in a higher level dungeon. That helped me get a good grasp of the Sage's toolkit.

EX: If you pop Kradia on the tank in Satasha and then spam Dosis, you can sustain them very well at Satasha (Lv 15).
Then you go to level 30 dungeons to practice how Eukrasia works and Phlegma for positioning.
Then you go to level 45 to 50 dungeons to practice with your Sage Gauge, Icarus, and Soteria. At this point, you should be working on getting a feel on when to heal, and how much you can use your passive healing from Kardia to sustain them.
Then to level 60 for new abilities - practicing how Zoe will augment your heals, when to best use Pepsis over your other healing tools, and how effective the upgraded Physis II works in tandem to your healing abilities.
Then to level 70 for newer abilities - figuring out when to use Taurochole and Haima, preshielding for Toxikon stacks.
And then you're set to where you need to be. You can continue the same pattern of learning at level 80 and level 90.

This is my preferred method of learning new classes. It lets you digest the entire kit of a class step by step instead of being dumped on by a ton of skills and trying to put the jigsaw puzzle together.

[ijuakos_xqwzts]

If you're really struggling, I recommend to go practice in a lower level dungeon first so it's not as if you get a full list of skills you have to figure out. This helps you consolidate a small section of the sage's toolkit at a time. After familiarizing with what you have learned so far, then you can go read tooltips for other skills, and then practice those skills in a higher level dungeon. That helped me get a good grasp of the Sage's toolkit.

EX: If you pop Kradia on the tank in Satasha and then spam Dosis, you can sustain them very well at Satasha (Lv 15).
Then you go to level 30 dungeons to practice how Eukrasia works and Phlegma for positioning.
Then you go to level 45 to 50 dungeons to practice with your Sage Gauge, Icarus, and Soteria. At this point, you should be working on getting a feel on when to heal, and how much you can use your passive healing from Kardia to sustain them.
Then to level 60 for new abilities - practicing how Zoe will augment your heals, when to best use Pepsis over your other healing tools, and how effective the upgraded Physis II works in tandem to your healing abilities.
Then to level 70 for newer abilities - figuring out when to use Taurochole and Haima, preshielding for Toxikon stacks.
And then you're set to where you need to be. You can continue the same pattern of learning at level 80 and level 90.

Zoe + Eukrasian Diagnosis seems pretty effective (or I've been coincidentally getting really good rolls from RNGesus every time I cast it)
One I've also been playing with is Eukrasian Prognosis -> Pepsis -> Eukrasian Prognosis. Done quick enough, it seems pretty good at getting a group burst heal.