How do I make Array-based buff system?

Hi I was trying to make a system where, when a item (like a sword) colide with an enemy, it adds to the enemy's buff array what can the sword inflinct, but it doesn't work, like, I wanted to, when the enemy's buff array has the "Burn" effect, it spawns a fire particle, but its not working.

It is very hard to understand what you are describing.

Perhaps write it down in a sequences of actions like this, and we can better understand what you want to achieve:

1) A collides with enemy

2) Something happens with B

3) Something happens with C

etc

If i'm understanding it correctly as an enemy status you can use an instance variable on the enemy object or family such as isBurn=yes. Equally if it is a case where the player inflicts burn you can use a global variable.

And how I stack their icons on the hud, like, when the player suffer from the "slow" effect, the buff's icon shows up?