What is the best way to 'position' items in menus?

Question

Alright, so i have completely gone through the HTML Tutorial and have learned the box model but whenever i use position in css, how would i make separate items without explicitly declaring where it should go.
Ex:
<header style="position:fixed; top: 0%; left: 0%; width: 100%; height: 10%; background-color: #00000">
<h1 style=""> <!--NOW HERE'S THE PROBLEM, DO I HAVE TO REDO IT IF I WANT A DIFFERENT PLACE?
</header>

Answer 1

Look into User Interface & Experience. UX & UI concepts will help

Answer 2

It depends on what you are trying to put in the menu. If you just want a logo then this is fine. But if you want something like a navigation bar you'd be better off using CSS Grid or Flexbox to position a bunch of items exactly where you want them.

Hope this helps