Template info needed

Hello,
I'm looking into a responsive template for my site and have a couple of questions. I've checked some other sites and see that when I view from my desktop I get an entirely different site than viewing from my mobile device. Are these two completely different sites? How does the device know which version to load? Sorry for my ignorance on this, I'm just getting into the 21st century. I'm going to download something basic to install and don't want it to look good on a mobile device but not on a desktop or <>.
Thanks

stedman:

Hello,
I'm looking into a responsive template for my site and have a couple of questions. I've checked some other sites and see that when I view from my desktop I get an entirely different site than viewing from my mobile device. Are these two completely different sites? How does the device know which version to load? Sorry for my ignorance on this, I'm just getting into the 21st century. I'm going to download something basic to install and don't want it to look good on a mobile device but not on a desktop or <>.
Thanks
The responsive templates that I'm familiar with all use the Mobile_Detect.php script (http://mobiledetect.net/) to determine the device type for which the page-view is requested.

Ok. Thank you very much for the reply! Do I need a mobile site and a desktop site? I notice some businesses have a site that is friendly to both but doesn't look that great on either as a result.

stedman:

Do I need a mobile site and a desktop site?

Maybe this could help you
https://developers.google.com/webmasters/mobile-sites/mobile-seo/overview/select-config?hl=en

Ok, I just put my original "module" file back up and things seem to work. Any idea why this would cause the problem with the new module file?