AR puzzles – How to add legacyAR module

Hi to all,
i’m now trying to add the AR module to my project, i read the documentation and used some parts of the AR example using the same button, class and id trying to avoid errors.
But when i click the “enter AR button” nothing happen.

I think the reason is because the app originally don’t have the legacy ar module, this can be the reason?

I also used a new tab named “AR” instead of the “Main”, this can generate this kind of issues?

Thanks to everybody in advance,
Marco