Special Effects is a action you have to find, its somewhere near the bottom.
So, basically, we'd do something like this:
Events - A unit acquires an item Conditions - Unit type of acquiring item equal to (your unit) Actions - Special effects - Attach special effects onto (your unit) on left hand using sword1.mdx
I Found A Easier Way Go To abilities Select Create New Find Item Capture The Flag Rename (left hand sheild iron) Change the attachment and attachment point easy as that removes it's self after dropped too