Hi,
It's actually very easy to do. The biggest issue is the page numbers and any headers or footers when you format in Word (or whatever word processor you use). Those need to be taken out before you save as a PDF. You want it to have only chapters and (ideally) you should have a table of contents with hyperlinks to the chapters (Unless it's a short story in which case it obviously doesn't matter). Then, just save as a PDF like you normally would, download
Calibre, click "Add Books" and add your story. Then, click "Convert Books," make sure the thing in the upper right hand corner says "epub" (I think that's the default) and click "OK." You don't have to change any other settings. Calibre will then save it as an epub. You just look in the folder where Calibre saved it and there it is, ready to be uploaded to the web.
If you want, you can also click "Edit metadata" and put in tags (basically category identifiers) by typing in whatever you want, separated by commas in the tags section, a description and whatever other data you'd like to include. Though that isn't necessary to do.
Good luck. If you need more help, feel free to PM me. I'm an author myself (though haven't published any of my gay fiction yet) and also a bit of a computer geek, so I know my way around all these things, but it's really very, very simple.
And thank you (and the other authors) very much for making your work available. It's much appreciated. I haven't had a chance to read them yet (been busy and have a backlog of other stuff to read) am very much looking forward to doing so.
Eric