@FlamesForAll no biggie, It can just get very confusing and cluttery at times.
Anyways, I’m not a Galilea Main or anything, but I understand more or less what she does/plays.
Here are the important bits for you from the Patch which explain Corruption.
Reduced the AoE of Corruption by 20%
Increased Corruption stacks from 20 to 40
Melee attacks gain 1 stack of Corruption
Skills gain 5 stacks of Corruption
So basically you can gain UP TO 40 Stacks of Corruption, it used to be 20. Melee attacks on enemies gain you 1 stack per hit while activating any of your skills grants you 5. You can gain UP TO 40 by using Skills and Meleeing things, which means you have to remain in the heat of battle to actually gain stacks. Stacks completely decay very Quickly when you’re not in Battle, like REALLY quickly. You’ll go from 40 to 0 after a few seconds of NOT meleeing anything or using a skill.
Now, This is important because some of her Helices and her innate Corruption DoT scale with the amount of Corruption you have. Helices such as Last Light and Antihero both scale depending on how much Corruption Stacks you have, meaning you’d need to be at Max stacks to gain their Max benefits.
Helices such as Sentinel Stance and The Pact help gain Corruption quicker. Although The Pact is in the same level as Antihero and Last Light which are two of the helices that you’d want to even have Corruption active for…so I don’t know about that…
So yeah, in summary; You gain stacks by attacking and using skills AND they go quickly when you aren’t doing either of those things. If you want more mileage on Antihero OR Last Light along with the DoT damage from Corruption’s purple bubble of doom, you best be in the heat of battle swinging that sword of yours.
Hope this helps.