The Live Traffic page shows the heartbeat of your site in real-time. It lets you watch visitors as they surf through your site and provides up to the second information on the number of visits and page views.
When a visitor clicks on an additional page on your site, that creates a new page view for that visitor. When you have checked the box to "Bump page views to top" that means when a visitor clicks on another page, their visit entry will bump to the top of the list showing an additional pageview. On very busy sites where many visitors are arriving, bumping page views to the top allows you to better see visitors who are visiting a second page.
These checkboxes determine what type of visitors are shown in the live view list. If you uncheck first time visitors, then only returning visitor entries will be shown from that point on. If you then check the box for first time visitors again, the live view list will again show first time visitors. It works the same with turning on and off returning visitors.
This is the page the visitor lands on when they visit your site. If I visit your homepage on Monday, my landing page is your homepage. If I surf around your site and find for example, a list of delicious recipes for chocolate chip cookies, I may bookmark that page. On Tuesday I again visit your site using the bookmark for chocolate chip cookies and go directly to the chocolate chip cookies page which would be my landing page.
This means the visitor arrived at your site by using a bookmark, by directly typing in your site URL into their browser or sometimes by clicking a link in an email.
