Pssssh. Wands of cloning, mirroring, and polymorph are simple (after a fashion).
Step 1: Lay down the items you want to clone, mirror, or polymorph. For cloning and mirroring, you can get up to 5 items cloned/mirrored, and for polymorphing you can get up to 25 items polymorphed if you lay them down in a straight line, 5 per tile, over 5 tiles. Note: If you have more than 5 items in a tile you use one of these wands on, you'll only clone/mirror/polymorph the top 5.
Polymorphing example: @*****. (@ = player, * = batch of 5 items, . = floor)
Step 2: Stand next to the batch of items or on either end of the line you created, then zap the wand in the direction of the items/item line.
Step 3: Reap the rewards. Note: when picking up from a stack you used a wand of mirroring on, you'll see (for example) a second stack of 5 scrolls underneath the first 5 rather than a stack of 10 scrolls - the top stack is the original 5 scrolls, and the bottom stack is made up of the mirrored copies; this is important because the mirrored copies have a limited shelf life and you really don't want to use up the wrong scrolls when mirroring things!
Also: in the event you wish to clone/mirror yourself, you can lay items down on your square and reap the benefits of hitting them as well as yourself, but you count as one of the 5 items, meaning that you will only wind up with 4 clones/mirrored copies of whatever items are on your square.