How do I deposit a coin on Poloniex?

As a cryptocurrency enthusiast, I'm often on the lookout for new ways to invest and trade digital assets. One of the platforms I've been considering is Poloniex, but I'm a bit unclear on the deposit process. Could you walk me through the steps of how to deposit a coin on Poloniex? I'd like to understand the interface, any verification steps required, and any potential fees I should be aware of. Additionally, is there a specific time frame in which deposits are processed, or are they instantaneous? Knowing these details will help me make an informed decision about using Poloniex for my trading needs.