How to install themes for a818 !

HP Pavilion dv7-6102sa QUAD CORE 6GB/1TB HD6490 BEATS
Exclusive "Dark Umber" HP Metal Finish! Warranty! until september 2013 john lewis 17.3 inch HP LED BrightView display with High Definition+ resolution (1600 x 900)! 6GB RAM DDR3! 1TB SATA HDD (~1000GB, 2 x 500GB)! 2.1GHz AMD Dual-Core A4-3310MX Processor - 2MB L2 Cache and up to 2.5GHz in boost mode! AMD Radeon HD6490 Dual graphic card with 512MB DDR5 dedicated memory! Beats Sound System with Subwoofer by Dr. Dre! DVD Dual Layer writer! Built-in Finger Print Reader! Multi-Format Digital Memory Card Reader! Built-in Bluetooth 3.0 High Speed! WiFi 802.11 b/g/n! 2 x USB 3.0 and 2 x USB 2.0 port! HDMI, Gigabit Ethernet and VGA ports! Built-in TrueVision HD Low-Light WebCam and Digital Microphone! QWERTY English UK keyboard layout! Genuine Windows 7 Home Premium 64-bit! excellent condition like new boxed and still under warranty by john lewis till september 2013