Carseat frustration

Jess

So I was given a carseat free from a friend and it looks like I'm not even going to be able to use it. It doesn't expire until 2022, but it's so ridiculously not user friendly. You cannot adjust the straps, I took it apart to clean it and legitimately Cannot get it put back together. And it looks like the only adjustment it does is the headrest part cranks up higher to tighten it, and that just seems janky to me. I'm still upset though because I feel guilty for it essentially being a waste. But I couldn't even find instructions for it on the manufacturer's website!

Anyone have any combination carseat, base, stroller sets they would recommend?