You can create your alias's as you build the site or if set to do so (settings->FURL's->automatically create alias) MODX does it for you. It will use the document name for the alias.
When you modify the url's within the document, use
src="[[++site_url]]assets/templates/yourSite/yourFileName"
so that when you move the site, it automatically pulls the new site address.
I'm not aware of any hard rule that says you can't use the FURL's while developing. One of the fabulous things about MODX is that you can use the MODX tags to make it so you never have to change any of the url's, regardless of where you move the site in the future. Just keep all your site files in the same location as you have in development and it all falls into place.
One tip I've been using lately which has simplified things nicely has been to set up a custom setting for my image files. I'm using
"[[++images]]imageFile.png"
before all my image files now instead of
"[[++site_url]]assets/templates/main/images/imageFile.png"
which works beautifully. Again, this allows you to move your site to your hearts content as long as all the site files remain in the original locations. (in settings, click "create new setting" button to make a custom setting)
The FURL's will update when you go live. I would turn it all on now so you can get a feel for how it works and looks.
I've found that even with the site in the root, pointing .htaccess to that specific folder is necessary. Pretty sure this is why you're seeing the folders instead of your site. In your case it'd be your username. When you go live, just change that to the new root folder name and it should work just fine.
And please... no worries about not knowing these things. It can be confusing. I've been re-reading through the Susan Sottwell's MODX information again, now that I'm not as confused as I was at first... it's making lots more sense this time (just substitute Revo tags for the Evo tags).
http://sottwell.com/how-modx-works.html
Additionally I've found Menno Pieterson's video tutorials and blog quite informative.
http://sottwell.com/how-modx-works.html
Mary's site also has tutorials a plenty to choose from.
http://codingpad.maryspad.com/
There's also a massive amount of Russian language video tutorials available on Youtube, etc. if that works for you. I wish I knew Russian!