I'd recommend reading through the various threads in the
Virtual Assistant Subcontractors section as well as here in the
Multi Virtual Assistant section. If you still have specific questions it's best to post them one at a time so that you get more responses (they'll be higher quality as well).
Regarding how to find VAs to work with, I can only speak from my personal experience - I always connect with VAs I know from networking here at VAF, based on what I see in their posts, their blogs, on their websites, etc. When someone impresses me and I have a job I need help with I always turn to this community. Generally, I'll reach out directly to the VA I have in mind, although in some cases I have posted an RFP or a Classified ad here on the site. I'm always making mental notes about who specializes in what, who writes well, who clearly has a lock on a specific skill, etc.
Spend a little time doing some homework here on the boards and you'll likely find answers to many of your questions.