setting up the smart tv box

I bought through ebay a smart tv box with android 4.0 shipped from china. There is no user manual and it is supposed to be built in as a help file. I have connected to my tv through the HDMI and got the home screen. I am unable to understand how to use the remote control as no pointer is seen on the screen that I can point and click. The arrows work randomly and I am unable to navigate the screen. I am able to get the browsers going but the navigation is a mystery.

When I click on the system set up, I get a series of choices, such as wifi set up, time set-up ( which I could successfully accomplish). When I try to customize the display size I cannot get the display to fit exactly to the screen ( it is spilling out of my 37 inch screen). There is no sound and what I should select the set up for sound is not clear. There is a wireless mouse included in the package and I do not know whether it is wifi and do not know how to set it up. I would like to set up the wireless keyboard that I already have with me. Are there special applications for these? Please enlighten me on the above points and help me use the full potential of the smart tv and android 4 capabilities.

The vendor was least helpful.