Answer 1

Umm well yes and no.
Depends on what you wanted it to do.
The comment is wrong and you actually wrote:
<p>Menu</p>
<p>Home</p>
<p>News</p> in order to make a navbar. that's not how it works

Answer 2

You can use W3C validator (https://validator.w3.org/ ) for more validation but the errors that jump to me right now is that you use <!== --> for comments instead of <!-- --> and you have multiple <h1> tags in your markup. Also the nav contains paragraphs instead of links

Answer 3

for nav area, you have a problem there. it should be
<nav>
<ul>
<li><a href="#"> Home </a></li>
</ul>
</nav>
follow this and see everything appear as you need it. and use <!--comments--> for your comments please