I have just received an Zenithink ZT 280 C 91 and as this is my first such machine I thought it would be easy to copy files from my laptop with the lead provided or to copy them to an sd card and read from that. This is not happening. The laptop did register but when I tapped on the file I wanted to open a tick appeared at the side of it but nothing opened obviously I am missing something. what should I be doing?