1. Install the template using Jomres 3rd party plugin installer (NOT Joomla Installer). Please make sure you don`t have installed JE Capella or any jomres gallery plugin (slideshow_fancybox or slideshow_carousel). For best looks use the default jomres slideshow. Also, make sure you don`t have any template overrides saved in the database using the Template Editing feature available in Jomres backend, because these will override JE Mira template files and the result won`t be as expected.
2. The jQuery UI theme can be selected from Site Configuration->Misc tab->jquery ui theme dropdown.
3. Go to the site frontend and see the new template in action.
JE Mira looks best on a 2 columns website, but may work on 1 or 3 columns websites too, with or without small modifications to css. This depends very much on the Joomla template you`re using and the space available in the main area, where jomres is displayed.