(someone) just (did something)

One of the uses of "just" is to express that something happened very recently. It can mean a few minutes before:

I'm sorry, he just walked out to go get lunch.

Or immediately before:

What did he just say?

Or it can mean a few years:

Mankind has just started to study ways to understand and control DNA.

But in any case, "just" means a short time before.

a guy

A "guy" is a man. It's a casual word.

You use this word instead of "man" when you're talking to your friends or in a casual situation like at a party. The person you're talking about can either be someone that you know, or someone who you don't know but don't have high respect for.

For a stranger who seems older and more respectable, "man" or even "gentleman" are more polite.

Note that you can use the plural form, "guys", when you're talking to a group of men or women:

Great job today, guys. Keep up the good work.

But "guy" (singular) always refers to a man.

(someone) in the (something)

You can talk about what a person is wearing with "in the ___":

the woman in the blue skirt

the kid in the gray hoodie

You can also identify someone with "with the ___":

the man with the big glasses

a fedora

A "fedora" is a kind of hat. It has a narrow brim going all around the head.

Fedoras were most popular in the mid-1900's.

wink at (someone)

When someone briefly closes one eye while looking at you with the other eye, they may be "winking at" you. Winking is a gesture that suggests that the winking person is sharing some kind of secret with you.

People sometimes use a wink to suggest that there's some kind of sexual attraction between them and the person they're winking at.

You can also wink at someone to show that you're lying to another person. For example, you might tell your brother that the dinner he cooked was really good, while winking at your brother's children to show that it actually wasn't very good.