Need help with a simple trigger problem!

Hi!

I need some help to create a simple trigger.
What I want to do for my RPG, is for the character to stack the potions he picks up. (for example, he carries one potion of mana, picks up one more, and instead of having two potions of mana, he has one with two charges)

I know it's a really easy one, and I also know I'm too stupid to figure it out :p

Please help.

Thanks

This tutorial by RaoDaoZao, may be of some help to you.

One million thanks to you.

This is rather old, but I couldn't find anything newer. When did we stop doing stuff with items?

A while ago, I guess. Seems a bit dumb that there's nothing else newer.