I'm playing Zelda - Skyward sword. I can't change items or things from my pouch or items collection. When I'm on the "item menu" I do as I'm told - I press and hold B to select, but the moment I let go all I get is a description of the item :( What do I do wrong?
What you're currently doing is viewing your inventory. What you need to do is either press and hold B to open up your "tools" pouch (slingshot, beetle, etc.) or press and hold the - button until your pouch containing your shield and bottles and whatnot opens. Then, still holding the - button, you can select the item you want.
If you want to move things around in your adventure pouch, you need to go see Peatrice at the Item check in the Bazaar in Skyloft. She will let you reorder the items in your pouch and let you pull things out as well.
You cannot, however, change any item in your collections or tool pouch.