Hello Jeanne,
Let me try to clear up some confusion for you and no worries about having these issues I once launched a plugin and broke the whole thing because there was a _ instead of a – so it happens to all of us.
You are correct you do have two folders and that is required. The Events Calendar Plugin stores all the main files and the Pro adds features to the main plugin.
The Events Calendar and the Pro should both be loading CSS so as long as the Pro is an active Plugin and the license is set in the Settings it is working. One quick way to confirm is if you have recurring events as that is a pro only feature.
Could you provide a link to the page you are trying to turn the background white and I can take a quick look. Is it the Event background you would like white and the site background is already white, correct?
Thanks!