vqi: U can use gold only. There is no button saying use item.

vqi: If u open 4 chests then u get 12 random items. Not 4 only.

_programmer_: ARENA you can found it in homepage
Arena
First, you must open 4 free chest to get 4x random item and gold. than use it
Next, Start Battle You Will Got WON!! And you will got trophies +25 or more
if you have the best much trophies you will see in leaderboard in rank #1
AttENTION!
In, battle if you lost, your trophies will lost -25 or more
so.. if your health is 5 left i think you must stop and rest for 5 minutes and your health will back again 100% and you will won the next battle

Regards,
_programmer_