hugo-theme-contentful/layouts/partials/header.html

{{ if not .IsPage }}
<header>
    <h1>{{ $.Site.Title }}</h1>
    <nav>
        {{ range $.Site.Menus.main -}}
        <a href="{{ .URL | absURL }}">{{ .Name }}</a>
        {{ end }}
    </nav> 
</header>
{{ end }}