Republican debate: What to know

The 2016 presidential race will reach a new level of intensity Thursday as 17 Republican Party candidates take part in the opening debates of the campaign.

Here's what you need to know:

WHAT AND WHEN: The top 10 candidates -- selected by Fox News based on the average of the five most recent national opinion polls conducted before Tuesday's deadline -- will face off in the prime-time debate from 9 to 11 p.m. That group includes Donald Trump, the leader in the GOP polls, as well as former Florida Gov. Jeb Bush, New Jersey Gov. Chris Christie, Florida Sen. Marco Rubio, Kentucky Sen. Rand Paul, former Arkansas Gov. Mike Huckabee, Wisconsin Gov. Scott Walker, Texas Sen. Ted Cruz, retired neurosurgeon Ben Carson and Ohio Gov. John Kasich.

The bottom seven candidates in the polls -- including former New York Gov. George Pataki, former Texas Gov. Rick Perry, South Carolina Sen. Lindsey Graham, former Pennsylvania Sen. Rick Santorum, Louisiana Gov. Bobby Jindal, former Hewlett-Packard CEO Carly Fiorina and former Virginia Gov. Jim Gilmore -- will participate in the undercard debate from 5 to 6 p.m.

WHERE: Quicken Loans Arena in Cleveland

HOW TO WATCH: Fox News will broadcast the proceedings on air and online at FoxNewsGo.com, including coverage between the separate events and after the prime-time debate. The cable network is hosting the debates along with Facebook and the Ohio Republican Party. Live chats will be held during the debates at facebook.com/foxnews, and chats will follow both events on FoxNews.com and its apps.

TWITTER: The official hashtag is #GOPDebate.