Email marketing can be so powerful! There are lots of courses on email marketing in the HubSpot Academy. For designing a clean email, you can start with a template or build your own with the drag and drop editor. Sending in bulk means you'll need to set up segments for sets of people to email at the same time. Segmenting will be based on setting up custom properties to help you identify who should be in which segment.
I'm an email marketing specialist. I'd be happy to chat with you about a few training/consulting hours as you get established in HubSpot. I also provide ongoing email marketing services if that interests you. Hope this helps!