The phrase "couple of things" means a small number or two, not many. It is often used to indicate that there are only a few points someone wants to make or discuss.
Alright, if you are planning to order this game, you need to know couple things about it. (amazon.com)
And how we lead our companies, makes all the difference in the world in whether you're on the front line or you're the CEO, we all want just couple thing in our careers. (lawyerist.com)