Hi,
it depends on what you've changed.
Because there is a need for relative paths in templates/css, we have to copy all templates to data directory from modules directories.
After modifications in .tpl, .css and any file located in modules/<some module>/theme you have to run Theme-up procedure
Open <epesi address>/admin/ - you'll have admin panel there.
Run 6. Rebuild common cache & default theme each time you have changed something.
To speed up this process you can pass GET argument to run action immediately.
For my localhost installation it's
http://localhost/epesi/admin/?module=ThemeUp&step=1
Adjust url to your own. Refresh this page each time you've modified template or css. Browser should receive new file after full refresh of EPESI site (F5, Ctrl-r, etc). In most cases you don't have to clean browser's cache.
Regards,
Adam