The light-table component exposes 3 contextual component (head, body, and foot).

{{#light-table table as |t|}}

  {{t.head}}

  {{#t.body as |body|}}
    {{#body.expanded-row as |row|}}
      Hello <b>{{row.firstName}}</b>
    {{/body.expanded-row}}

    {{#if isLoading}}
      {{#body.loader}}
        Loading...
      {{/body.loader}}
    {{/if}}

    {{#if table.isEmpty}}
      {{#body.no-data}}
        No users found.
      {{/body.no-data}}
    {{/if}}
  {{/t.body}}

  {{t.foot}}

{{/light-table}}

Each of these contextual components have a wide array of options so it is advised to look through their documentation.