Just install it and if you reach a Website with malicious code inside there will be a popup asking you wich app to launch. Just select "use as standard" an choose NoTel:URL as app and you will be fine.
Starting with Version 1.1 of the App, malicious USSD Codes are shown within a popup Window. To gain best protection there is no way to execute USSD codes. If you klick on a valid phone number within a webpage or received by barcode you are able to execute the request if your Android OS Version is >= Ice Cream Sandwich.
Below this Version there is no way to directly rout the number to the dialer, so you need to do this manually by typing the number in the dialer.
There is no need to start the App manually. If you do so, there will be an explaining Popop now.
Everything will went automatically if the app is just installed.
Detailed Information can be found on my Website:
Here you will also find urls and barcode for testing
Keywords: USSD, security