Okta IDP Redirection based on the email id

I am new to okta and first time i am integrating okta in my web app, I have used OIDC way to integrate okta in my app and it’s working as expected, but i want following behavior:

  • when user open login page at that time i just want to show email id field using okta signin widget (currently okta signin widget rendering two filed username and password)

  • after that based on email id i want
    1st case - i want user to redirect user to third party login service i.e google
    2nd case - i want user to stay on same page and password field will be appear

I am referring this DOC , but it’s not working for me.
Please help me if anyone came accros samme functionality or have some idea how to implement same kind of thing.
Thanks a ton in advance!!