Good day all, i just bought a Rosen piranha in dash nav radio model UN1170-CA l would like to install Tomtom on it because I'm used to the way it works. I am a complete newbie on this but am a fast learner. I already put in a sd card and did a backup of the current navi software (not sure what it is though) but have no clue what my next steps are. Please advise so I don't mess up the unit. thank you in advance.