Jason,
Each kind of engagement nurture can be very different, so it depends on your goals and how you are structuring these emails. What is the CTA in each email?
For Engagements, see:
http://www.marketingrockstarguides.com/marketo-engagement-program-and-nurturing-testing-959/
http://www.marketingrockstarguides.com/how-to-use-marketo-engagement-programs-850/
http://digital-pi.net/2013/10/marketo-multi-stream-nurturing-on-a-single-stream/
For nurturing see:
http://www.marketingrockstarguides.com/marketing-rockstars-guide-to-marketo/
and
Definitive Guide to Lead Nurturing via Marketo.
Yes, once you set up the Streams and content, you will need two campaigns to kickstart it:
01 - Kickstart - Batch
02 - Triggered Add ---- this one adds people as they come into the system.
You will also need an Exit flow in some situations.