download code for asp.net 3.5 yourself
do modification accordingly.
then to add download functionality
go to default.aspx page under
<script id="template-download" type="text/x-jquery-tmpl">
<td class="name">
<a href="${url}/Website6/Uploaded Files/${Name}"{{if thumbnail_url}} target="_blank"{{/if}}>${Name}</a>
</td>
instead of website6/Upload files
you can specify your folder path where u store the files.