U.S. Sen. Bernie Sanders (I-VT), right, president of the South Carolina NAACP chapter, Brenda Murphy, march to the Statehouse in commemoration of Martin Luther King Jr. Day on January 21, 2019 in Columbia, South Carolina.

Sen. Bernie Sanders and his advisors have been meeting with potential South Carolina campaign staffers as the Vermont democratic socialist looks to pull off a win in the state's 2020 presidential primary, four years after Hillary Clinton crushed him there, CNBC has learned.

Sanders has been pushing to firm up his support among younger and more liberal voters. According to people familiar with the process, the senator has been flying possible hires to his home in Vermont and having in-depth conversations about how they can help his operation.

This time, Sanders faces a bigger, albeit more diverse field of Democratic rivals, and he has fallen behind in the South Carolina staffing race. Sens. Kamala Harris and Cory Booker were among the first to start staffing there. Booker hired former Sanders state political outreach director Christale Spain to be his 2020 state director. Sen. Elizabeth Warren on Monday announced South Carolina hires, including Alycia Albergottie, who was Clinton's 2016 state director.

Sanders is also looking to make inroads with black voters. In 2016, Clinton, who won the primary by about 50 percentage points, grabbed 84 percent of the black vote compared with Sanders' 14 percent. The senator has been in regular contact with supporter Terry Alexander, a South Carolina state lawmaker.

Sanders plans to expand his outreach to black voters, Alexander said.

"We are going to have a lot more events in the African-American communities this time around," Alexander, who is black, told CNBC. "I think you are going to have them more involved with the faith community, with the seniors and as a total community as a whole."

The 2016 United States Census Bureau survey shows 69 percent of Palmetto State election participants are white, while 27 percent are listed as African-American.

Alexander also elaborated on Sanders' hiring process.

"We have been looking at staff and setting up an organization here in South Carolina," Alexander said. "We had a conversations this past Friday about how it's going to look and how it's going to work for him. We are trying to find people who want to win and not just those who just want to be on a campaign. It's the question of do you want to win, and I want to win South Carolina."

Alexander declined to name the people he has met with about joining the campaign. He also noted he could play either an official local or national role for the campaign, and a decision may be made this weekend about his position.

Sanders will be traveling on Thursday to South Carolina for the first time since launching his campaign, hosting a rally in North Charleston. Prior to entering the 2020 election, Sanders in January spoke at a Martin Luther King Jr. Day rally at the state capital and later at the historically black Benedict College, where he recounted marching with King in the 1960s.

Representatives from the Sanders campaign did not return repeated requests for comment. Senior campaign strategist Jeff Weaver confirmed on a phone call with reporters on Monday that Sanders and his advisors have been working to put a team in place in the five early primary states, which includes South Carolina.

When asked how he will do better in 2020 within the state compared to the last election, Weaver said the campaign will have "a stronger team on the ground and be much earlier in the process."

Sanders campaign manager Faiz Shakir announced they had 70 people on the national payroll.

President Donald Trump won the state over Clinton in the general election by more than 14 percentage points.

Democrat Joe Biden and his consultants have been reaching out to seasoned political operatives in the state to see if they would join the former vice president's operation if he runs, according to people familiar with the discussions who declined to be named.