Pending Funds Question

I just made my first major deposit into the Public App so I can invest my first big chunk. The funds are still pending, but it cleared and gave me that amount in buying power, and I was able to invest and I now have two pending orders and still some cash in my buying power account. It's all labeled under “cash” but none of it is settled or withdrawable. My question is: since I was able to buy with it, does that mean my bank already cleared it? When do pending buys clear and officially become trades? I know kind of noob but this is my first go at something like this.