Help with coding simple Hubspot submit form

I am using an embedded Hubspot form on a website for an email subscription. This is done using javascript and looks like attachment 1. I'd like to change the format so it looks like attachment 2 (single 'Quick Subscribe' with integrated button).

Here's some info on how to customise: https://developers.hubspot.com/docs/methods/forms/advanced_form_options

I'd like someone to provide the code to do this - and instructions as necessary.