How to phase in BP Daily?

I downloaded, uploaded, and activated the BP Daily theme onto an unlisted subdomain on my urban planning multi-site network. Per the installation directions, I activated the child theme but not the parent theme. Anyway, I'm a noob and the only theme I've ever used is the atahualpa theme, which allowed you to import the formatting and style from the main site or another subdomain. I'm not sure where to begin. I'm not even sure I understand the parent child concept.
1) Am I doing it right by using a child theme at this subdomain?
2) If I get it set up the way I want it, will I be able to import the style and formatting to another subdomain, or even the main site?