Hello Trevor,
If you are using the free version of WPDM and using the default template, you can edit the link-template-default.php
file. you can edit it from download-manager\src\Package\views\link-templates
dir. For making backup your file you may follow this doc,
Template Files
And for related template tags, please check this doc,
Template Tags
please let me know, how can I help you more?
Thank you and regards