I went to main screen tap on More (+) > next screen (right) > Help > About > More > Content . but there's no "3D landmarks" as an option.

Sorry, did you confused me with someone else? I didn't received any tutorial from you nor followed a tutorial from this site on how to install igo primo 2.4, I tried searching for the tutorial on this site, though, but couldn't find one. Instead, I followed a 2011 tutorial written by Fatboyfun from another forum.

I just did more searching, now, and I still can't find the tutorial on installing igo primo 2.4. sorry. Can you tell me where the tutorial link is, please?