How can I prepare dried minced garlic?
You probably do not want to simply dry it on a plate, as it may mold or spoil prior to drying.

When I checked the National Center for Home Food Preservation, I was unable to find any information on drying garlic.  I was also unable to find a single University Extension that provided instructions on safe methods for drying garlic.

If you google homemade dried garlic, you will find multiple recipes and methods, although powdering is more common than mincing.  None of these recipes or methods come from the most reputable sources, so use them at your own risk.