Where to I find my site's files?

I’ve been told that I need to remove all the files and folders under your site’s /wp-content/cache/supercache/

but I don’t know where to start looking for the files – I feel like I should be able to find them but no luck so far! I have already deactivated and deleted the plugin but I need to get rid of all traces of it.

Thanks so much to anyone who can help.