Like, I know someone that has to watch TV every night before he sleeps in order to wind down.
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Q1. Does 'Like' mean 'You know' or 'Guess what'?
Q2. Does 'wind down' mean 'relax'? Dow you use those expressions frequently?
"Like" is slang and is used only in informal speech. It's an extra word that's unneeded! But kids love it, and some can hardly speak without sprinkling it throughout their sentences! In your sentence above, it seems to mean, "For example..."
To "wind down" means to relax, yes. In this case, the "i" in "wind" is long -- sounds like "eye." (As opposed to when the "wind" is blowing, and the "i" is a short sound.)