Can you answer my noob questions?

I am just a newbie when it comes to site creation, though I have a small background in HTML but I am too lazy to review stuffs regarding considering the fact that it has been almost quite some time since I studied and used HTML properly. I had my basic HTML lessons way back in high school and freshman year in college, with that being said I opt to join yola since it seems to be a good site builder for newbies or people with no html knowledge.

Now, I am planning to create a personal site to advertise some of the online earning sites that I use so basically I will create a site consisting of a lot banners and referral links.

I want to know whether the free "yola.com" domain will be sufficient for my needs. Also, since I am planning to buy a domain from you, is it advisable to create first my free yola.com site then just link the domain to it? I am quite confused, or should I buy a domain first then link it to a site?
Lastly, what does linking really do? Does it just forwards your site visitors to the old site? Or it completely changes the name of the old site like "money.yola.com" to "money.com"