The editor prompt me include content not permitted... This is my content: And I don't know why this content not permitted...

I am a total newbie developer so I thought I would start with the Landmarks tutorial. I managed to go through the whole tutorial and I wanted to change the whole category list with something totally different. I'm not familiar with Json at all but if I try to change photos with others that I added in the assets folder everything good but the references need to be changed I guess with a new id that needs to be created and other files that are affected but I'm not sure where to start because I want to change the description text and coordinated in the map as well. Also I would like to descriptive reference to various you tube videos relating to the different topics.