Open the back cover (where the battery is inside), inside on one of the short sides is a sticker that says:
WiFi SSID: <wifi name>
Key: <here is the password that came with the device>

To change the password:
On the right side of the same sticker it says:
IP: <URL>
Pass: <XYC>
Use the wifi of your U50 to connect a laptop or smart phone to the internet.
Then open a browser on this device and connect to the URL behind "IP" on the sticker
On the website that opens, there is a field where you type in the "Pass" that is on the sticker
Then go to WiFi Settings
Then Main SSID
There you can change the Pawword
Good luck!