How does one delete unwanted tags? I made some then got a better idea and made different tags.

The tagging interface should allow you to delete your own tags; if that doesn't work, go to the config directory (settings/manage resources/open resources directory) and edit that tags files.

I haven't found the way to do that via the tag interface yet.I guess I've been exploring everything so fast I must have overlooked it.

If you are referring to the tags for the Brush Presets, you can do this in the Windows version by selecting the tag you want and clicking the green plus. You should then have the option to "Delete this tag". Not the most intuitive interface but it is there

I figured it out last night, before your post, thanks though because you explained it really well.