A finding aid is roughly speaking divided into two parts: the "front matter"; the inventory. Here is a simplified view.
<ead>
<!-- begin "front matter" -->
<eadheader ...>
<frontmatter ...> <!-- the frontmatter element -->
<archdesc ...>
...
<!-- end "front matter" -->
<!-- start inventory -->
<dsc ...>
<c01 ...
<c02 ...
<c03 ...
...
</dsc>
<!-- end inventory -->
</archdesc>
</ead>