Thank you for reaching out to us here at T-Mobile for assistance @Pabloco89, here are the steps to follow to configure your new device:
I would first follow this getting started guide for configuring your device to your computer with the default settings.
If you are unable to see the network or unable to connect to your new mobile hotspot with the default SSID and WiFi Password I would then follow the procedures outlined on the following document:
After you have connected your device to your computer it will probably re-direct you to our T-Mobile website whenever you attempt to browse any website and that is due to not having an account configured for that device, here is the information for the plans that we have available for our Mobile Broadband Devices:
I am confident that with the information provided here you will be able to succesfully configure your new device and enjoy your new T-Mobile service. Congratulations on your new Mobile HotSpot and I'm confident you will enjoy it.