How can I know that I am on the official PattiePad page?

The official PattiePad site is https://pattiepad.com There are NO other sites for PattiePad. Other sites are created by scammers.

https://pattiepad.com

Don't ever follow other links.

Someone sent me a private message in Telegram and told me they were from PattiePad. Are they real team members?

Admins or the PattiePad team members never DM you first. Never give your info or any credentials like your wallet seed phrase or keys to anybody. Never follow links or open documents sent by these actors, consider them always scammers. Just report spam and block them.