Requirement: You must have Resurrection Level 1 or higher. (In official server, there is a job level requirement of 40 or higher.)
Talk to her until she finish talking, then talk to her again.
Bring the required items to her and she will try to teach you the skill.
There is a chance that you will fail to learn the skill, in that case, one of each item will be taken. You must have at least the required amount of Holy Water and Blue Gemstone in your inventory to try and learn again. So it's recommended that you bring 5-10 more of each.