Understanding keychain I am having a hard time understanding how does Keychain works, whats the default setting for it as long as i dont touch anything? and what if I don't remember my first password?
Can someone explain me?

Thanks
Your default keychain that holds the login info/wifi passwords, etc is called login. If you forget the password, you can reset it from Keychain preferences. It is usually the password of the account when you first created it. Refer to Apple's support documentation for more information:

https://support.apple.com/en-us/HT201609