Simply create a ==Related projects== section, somewhere on your US-related WikiProject page, usually at or very near the bottom, add {{US-related WikiProjects}} to that section and save the page.
This template's initial visibility currently defaults to autocollapse, meaning that if there is another collapsible item on the page (anavbox, sidebar, or table with the collapsible attribute), it is hidden apart from its title bar; if not, it is fully visible.
To change this template's initial visibility, the |state=parameter may be used:
{{US-related WikiProjects|state=collapsed}} will show the template collapsed, i.e. hidden apart from its title bar.
{{US-related WikiProjects|state=expanded}} will show the template expanded, i.e. fully visible.
