Based on the information found on the official website, all EzCast dongles support the following technologies: Miracast, DLNA and Airplay. This means you need one of this technology in order to broadcast content to the dongle. The EzCast dongle can be connected to a WiFi source and then you can use that source and devices on the network to broadcast content to the TV.
Also, you have to configure the dongle first before connecting. Insert it into USB, switch to HDMI interface and then use the remote control to configure it.