I'm just passing along this offer as a formality.

我只是按规定传述条件。

But since I'm going to ask you some questions here at the police department, I'd like to advise you of your rights, more as a formality, if you're OK with that.

但既然我要在警察局问你一些问题，我想告诉你你的权利，更像是一种形式，如果你同意的话。