Triggering. Its hard if you don't know much about it, like myself. However I can try to give you an idea of how it might work.
I don't know off the top of my head, but let's say you want hero to get Blue shield and Red shield to have them combine and become Purple shield. In the trigger you would have to set Blue shield to integer variable 1, Red shield = 2, and Purple = 3. Now you have them 'labeled' for the trigger.
Next, you must include a code stating when your hero has both items in his inventory, take those two items out and place the third item in his inventory instead. "Unit (triggering unit)" means any hero that will trigger the effect of having blue sh. and red sh.
So it would be something like
Condition: Unit (triggering unit) inventory Blue Sh. = true, Red Sh. = true.
Action: Remove Item Red Sh. and Blue Sh. from inventory. Place Item Purple sh. in triggering units inventory.
Then one final command to let the trigger know its done i think. Again I can barely even call myself a beginner at triggering, but from studying other triggers I gathered this much about item combination.
