Suman

Hello Brenda,

Can you please share your link Please?
Also you can check Database users table does it shows you the same username?
Have you tried to Reset Password?

Thanks
Suman W.

Hello Raghvan,

Firstly WordPress Theme Twenty Fifteen is old version so it does not have page template.
You can check more details of this theme here.
I will suggest you to use the latest theme Twenty Seventeen developed by WordPress.
Also to learn about how to convert HTML to WordPress Theme, this tutorial can help click the link here

Hope this helps

Thanks
Suman W.

Hi StephenEquus,
Yes you can leave GUID URLs of staging same as production as it is not used to link Post.
So you can keep it as it is.

Thanks
Suman W.

Thanks for Updates.Let me check this. and get back to you soon.