Equiping on iOS

I may sound like an idiot asking this, but i've never been able to figure out how to equip certain weapons, armor, amulets, etc. on iOS. How do you do it? I started playing this game exclusively on my iPhone, but logged in with facebook. It wasn't until i had been playing for 2 weeks that i pulled up the game on Facebook, and found out the interface was totally different. And I was able to change my equipment on there. Which meant that i had a lot of strong equipment, but it was never automatically equipped in the slot because i never did that on iOS.

Make sense??

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