Playing around in wardrobe and there's the diamond style items like eyes and stuff that are locked behind diamonds I assume, but how do I buy them? Like eyes?

To buy the Wadrobe Styles that cost Diamonds() or AP(), in the upper right hand corner of the item, you click the satchel icon().

After clicking the satchel icon, you'll get a pop-up that'll let you buy the style. For AP styles, you can buy them with AP or Diamonds, while Diamond styles can only be bought with Diamonds.
Once the pop-up is on screen, you just have to press the green "Unlock" button on it if you're buying a Diamond style. If you're buying an AP style, you'll have to select whether you want to pay with AP or Diamonds, and the click the Unlock button.
After that, you'll have purchased the item so long as you had sufficient funds to do so.

For Diamond clothing, there's an Avatar Shop that offers some clothing bought with Diamonds. However, a lot of older clothing that cost Diamonds are only available during certain events, such as the Black Friday sale.
https://www.sylestia.com/shops/avatar/

Oh gosh I see now!! Thank you so much!!!!