Flex box

I can’t seem to get an agent on the phone or chat so this is a last ditch effort. My flex box came in and I followed the very slim instructions of plugging in the cords, but nothing happened. I thought maybe I had a faulty cord, so I tried to plug the HDMI cable into the input area, and the power light came on. Nothing else happened after that. I am at a loss. I have been trying to get help for over three hours and keep getting disconnected. Please, someone help me.