Jmeter Performance Testing DOM and Load time

1. What is the exact difference between DOM time and Page Load time. When I go to Google Chrome and Press F12 and go to Network, I see the DOM time and the Page Load Time and can this be implemented in Jmeter to get the DOM and Load time.

2. My second question is When I record my script in Jmeter and run it does each sample count as 1 Service as I need to run my website for 30,000 users.