So you wanna know how to use emoticons?
Below every text box you can see "Emoticons" - click there and a list of all of dA's emotes and their codes will appear, and you can arrange them in different categories.
If you're talking about the PLZ accounts, the command is
:icon[username]:
For example: :icon
imhappyplz: becomes
Hope it comes in hand
If you need help on anything just ask people, they'll surely stop to help