New C++ user - Incomprehensible (to me) errors, and I can't see an issue

I started C++ less than a week ago, because it seemed like a very widely use language, and a good one to learn, as many say it makes learning other programming languages easier.

Code

Error Feed

As a new user, I have no idea how to start to understand what these errors mean, and how to fix them.

I would greatly appreciate help with this, and any advice on how to avoid such errors.