Winter 15 is a wordpress theme, Coded is Php, HTML and CSS. Installation process is just similar as all other themes. All you need to do is just open your wordpress dashboard then navigate to Appearance->Themes-> Add New -> Now upload the .zip file (you downloaded) into that and then you'll see an option of 'Winter 15' in themes section. I have tried to make the look and feel of theme as simple as it can be done. Feel free to drop and email to me at rkking@live.com if need further help. One more thing before you start using Winter 15, there is just a request please don't remove the footer 'Crafted by heart in India' that'z all i need.