Apply theme to Single Page in a custom Package

Permalink
hello, im rather new to this process an was having a few problems i was hoping to get clearer answers on.. I'm attempting to add a custom package to my site, inside my package i have already successfully created a theme to be applied an it works fine so far. My next step was creating a single page in my controller (not too difficult thanks to a few links). Now that i have my themem an my SinglePage my next mission is to only apply my theme to the singlePage upon install. Sounds simple but it seems that is not the case.. So im wondering if this should be defined in the Single Page controller? ormaybe the theme's theme_page.php? im almost completely lost when it comes to working with controllers an cant find good documentation online..So to Clarify: I need a way to apply my theme to only the SinglePage(s) included in my package. Is this Possible?