Control path for custom project tab in PerfexCRM

I am developing a module for Perfex CRM, basically, I will integrate a custom 3rd party Invoice software with Perfex CRM.

I manage to add a new Tab in Projects -> Project View: https://prnt.sc/38uOB1YAaqs6

But I can't manage to change the path of the file, even if I use class Clients extends ClientsController in myCustomModule/controllers/Oblio.php

It still gives me this error: https://prnt.sc/yk1Tkt7WLsA_

Any help? The documentation's not so helpful.

Thank you!