I purchased lightroom presets and the presets are not in my "downloads" folder as promised.  I purchased the presets from FS*Adobe and paid the $19.00 required.  This is the first time I have purchased presets so I don't know what I am doing!

I'm not familiar with the presets or the company you purchased them from. But I suggest you contact their customer support for assistance on downloading and installing the presets.

Assuming the presets came bundled in a ZIP file, after you click on the link, you do need to pay attention to where your browser wants to save the file.

Doing the download again should not harm anything.