Account Engagement Email vs Email Content vs Email Templates Wizard

Hi Community,

I'm new to account engagement and am navigating the learning curve to start creating email templates for communication. Although I've gone through several Account Engagement (Pardot) trails, I still feel unclear about some aspects.

Could anyone please help clarify the following points?

1. To start emailing my existing leads and contacts, do I need to export them as prospects in the Account Engagement app? Note that these are historical contacts.
2. I want to email a list of prospects/leads/contacts using custom pre-built templates. Should I create these templates in the Account Engagement Email wizard or the Email Templates wizard?
3. The email builder in the Email Content wizard is different from the ones in the Account Engagement Email wizard and the Email Template wizard. If I create a template in the Email Templates wizard, how can I use that specific template in the Account Engagement Email wizard?

I've always used drag-and-drop email builders and have limited HTML/CSS experience. Also, if anyone could point to me to some additional documentation, that would be great.

Thank you!