You attempted to change the channel, and the TV went blank or snowy.
You may have changed the channel on your TV set, not the STB (if you used a grey Amino brand remote or you used your television`s remote).
You may have accidentally turned the STB off.
What to Do
Turn the TV off and on again, then note what channel/input displays when the TV first comes back on. If it is the wrong channel or input, tune the TV to the correct one.
On your remote, press the STB or CBL button, then press the Power button.