Lauma is a very simple character: you use her Elemental Skill, then use her Elemental Burst.
Her tap Skill is preferred when run with Nefer and without Columbina so as to leave sufficient Verdant Dew for Nefer. Outside of this, Hold Skill is preferred: Columbina both provides additional Verdant Dew through her passive and consumes Lauma’s quills when dealing damage, while teams where Lauma is the sole Lunar-Bloom unit tend to burn through her quills because of the constant reactions while also having no other use for Verdant Dew.