Please teach me what to do about this lawn

So I am a first time owner and justices into my new home.

I am trying to figure out what to do about my lawn.

I tried removing the visible weeds, but I am not sure whether the plant in the pic is also weed. There are a lot of them and removing them all pretty much leaves the yard barren

Also, in the unfortunate case that weed indeed has taken over my yard, what is my best course of action? Anything I should get done before the winter? Or should I just wait till next spring and have a professional company handle it?