Lightbox pop up - incorporating form

Hi there,

I am a complete novice to Adobe Target but i wonder how i might incorporate a form to capture email address 'properly' within the Lightbox pop up template found here https://docs.adobe.com/content/help/en/target/using/experiences/vec/modifications/experience-templates.html.

At the moment we can pop up but the 'sign up now' CTA would link to another page which isnt the best CX/UX. 

I can also see the examples on link below, but is this custom code editable at all?

https://github.com/Adobe-Marketing-Cloud/target-experience-templates/tree/master/lightbox

is there a way of including an existing AEM component (newsletter sign up in this instance) into the pop up itself?

Thanks