If Outlook won’t accept your password and you know you’re using the right password for your Gmail account, you might have an older version of Outlook that doesn't currently support this faster Gmail setup option. If you need instructions for adding an email account using advanced settings, see Use advanced setup to add a POP or IMAP email account in Outlook for PC.
Installing Outlook Mobile is a great way to stay up-to-date on the go. If you check the box for Setup Outlook Mobile on my phone, too, you'll be taken to a website where you can enter your mobile phone number and you'll receive a link to download Outlook for iOS or Outlook for Android.