improve pageGrid docs

Author: a-hariti

docs/contributing/pages/components.mdx

@@ -119,9 +119,19 @@ See also the [Alert component](#alert).
 
 ## PageGrid
 
-Render all child pages or `next_steps` of this document, including their `description` if available.
+Render all `next_steps` of this document or default child pages, including their `description` if available.
+
+You can specify `next_steps` in the frontmatter of a page to include them in the grid. It supports relative paths and will automatically resolve them.
 
 ```markdown {tabTitle:Example}
+---
+# in the frontmatter of a page:
+next_steps:
+  - ./child-one
+  - ./child-two
+  - ../parent/child-three
+---
+
 <PageGrid />
 ```