Como usar "To get something straight"?

I heard the following expression on the AMC's The Walking Dead "Let's Get one thing straight, this isn't democracy anymore."
Can I use it in the following way "I'll get one thing straight..."(Eu vou deixar algo claro)?
In other words:
(x) Let's get one thing straight(Vamos deixar algo claro/bem claro)
(x) I'll get one thing straight(Eu vou deixar algo claro/bem claro)

Thanks a lot!!