The First View
row is a test that was done with a browser that had its cache and cookies cleared out and represents what a first-time visitor to the page will experience.
The Repeat View
row is a test that was done immediately after the First View test without clearing out anything. The browser window is closed after the First View test and then a new browser is launched to do the Repeat View test. The Repeat View test represents what someone will see if they are coming back to the page some time after visiting it the first time (and is a best-case scenario since the test is re-visiting the page immediately).
The metrics grouped together under the Document Complete
The metrics grouped together under the Fully Loaded
The Load Time
is the time from when the user started navigating to the page until the Document Complete event (usually when all of the page content has loaded).
The First Byte time is the time from when the user started navigating to the page until the first bit of the server response arrived. The bulk of this time is usually referred to the "back-end time" and is the amount of time the server spent building the page for the user.
The Start Render time is the first point in time that something was displayed to the screen. Before this point in time the user was staring at a blank page. This does not necessarily mean the user saw the page content, it could just be something as simple as a background color but it is the first indication of something happening for the user.
The DOM Elements metric is the count of the DOM elements on the tested page as measured at the end of the test.
This is the amount of data that the browser had to download in order to load the page. It is also commonly referred to as the "Page Size".