Long and short
Long = you profit if price rises. Short = you profit if price falls. In futures, shorting is as easy as clicking sell — no borrowing, no restrictions.
Leverage
You control a big contract with a small deposit. 1 NQ contract might control ~$400k of index exposure with only a few thousand dollars of margin. That's leverage.
Margin
Margin is the deposit your broker requires. Intraday margin is often much smaller than overnight margin. If your account can't cover a losing position, you get a margin call — or your position is auto-closed.
The trap
Leverage doesn't create edge — it magnifies whatever edge (or lack of it) you have. New traders blow accounts by treating leverage as free money.