Not that much it multiplies power by 0.5.
In your list of items press a on the item you want them to hold then in the list of options it should say Give and then shows a list of the Pokemon in your team then press A on the Pokemon you want to give it to.
Train it, give it items, have it hold soothe bell.
your Pokemon can only hold 1 item at a time also it can only hold items that you give it on Pokemon pearl, diamond, or platinum so if you give your chatot an oran berry than that's what itll have on battle rev.
Train your pokemon, Give it items, Have it hold the item Soothe bell.
Catch Paras/Parasect you can take it from they as hold items
Nothing really, above and beyond using it as a hold item. It is Palkia's signature hold item and lets Palkia have it if you migrate one over (pokemon can't bring items across, so that's how they give you the Sinnoh trio their hold items).
You can't, unless you give it the Bright Powder to hold, which increase evasiveness by 10%.
make it hold a soothe bell. make any pokemon hold the soothe bell and it'ss increase it's friendship
you can get them prettymuch anywhere you go. Pokemon hold them in amity square and some people just give them to you.
Unfortunately not, but it is possible to clone items
no you can't let Pokemon hold key items
You need to have a Pokemon hold the item then trade the Pokemon.