[SOLVED] How to create a new menu/page ?

Hello, it's me again

I've looked around and did some googling but I couldn't find any explanation on how to add a new page to ProjeQtOr.
I'd like to create a similar page as the "Email Template" one. I've found the "menu" and "navigation" tables in the database and added a new line in each corresponding to the class I added ("TelegramTemplate"), but nothing happened.
How can I achieve this ?

As usual, I've found the answer and it was particularly dumb. I didn't change the habilitations for the menu...