1. if you want a dsdt (tbh the native one should be fine for you, dont know why youd want to modify it) but if you do, use the guide in my sig, and use the asus "generic p8 3xxx" patch on olarilla. itll make sense when following the guide.
2. you have to use the usb flashback feature to flash the modified rom. you cant use ezflash2, as if you do youll get a security check failure. read the manual for more info on usb flasback