... the South Carolina Republican Party shall conduct a statewide presidential preference primary on a date within two weeks after the New Hampshire Republican Primary or earlier if necessary to preserve South Carolina's "First in the South" status. [South Carolina Republican Party Rules - Rule 11(b)(1)]

Saturday 20 February 2016 (presumably): South Carolina Primary. Hours 7:00a-7:00p EST (1200-0000 UTC). Delegate Selection: Winner-Take-All (district and statewide) Primary. Voter Eligibility: Open Primary.

Primary
Source: South Carolina Election Commission.
Status: Official. Retrieved: Thursday 24 March 2016.
Included in Nationwide vote.

Saturday 20 February 2016 (presumably): All 50 of South Carolina's delegates to the Republican National Convention are allocated to presidential contenders in today's South Carolina Presidential Primary. [Reference: The Rules of the South Carolina Republican Party as amended by 2015 South Carolina Republican Party State Convention]

• 21 district delegates are to be allocated to presidential contenders based on the primary results in each of the state's 7 congressional districts: each congressional district is assigned 3 National Convention delegates and the presidential contender receiving the greatest number of votes in that district will receive all 3 of that district's National Convention delegates. [Rule 11(b)(4)]
• 29 (10 base at-large delegates plus 16 bonus delegates plus 3 RNC delegates) at-large delegates are to be allocated to the presidential contender receiving the greatest number of votes in the primary statewide. [Rule 11(b)(5)]

Primary
Source: Email from the South Carolina Election Commission.
Status: Official. Retrieved: Saturday 26 March 2016.

Each congressional district delegate ... shall be bound during the first ballot at the convention to the presidential candidate who received the greatest number of votes .... If the candidate who received the greatest number of votes in that particular delegate’s home district is not placed in nomination, a delegate must then be bound to the congressional district's second or third place finisher in the presidential preference primary, respectively. If none of the top three finishers in the congressional district presidential preference primary are placed in nomination, delegates shall be unbound.
Each delegate-at-large shall be bound for the first ballot to the candidate who received the largest number of votes statewide in the presidential preference primary. If the candidate who receives the greatest number of statewide votes in the presidential preference primary is not placed in nomination, a delegate must then be bound to the state's second or third place finisher in the presidential preference primary, respectively. If none of the top three finishers in the statewide presidential preference primary are placed in nomination, delegates shall be unbound. [South Carolina Republican Party Rules - Rule 11(b)(4), (5)]

March 2016 (presumably): The County Conventions convene to elect delegates to the District and State Conventions [South Carolina Code of Laws - Section 7-9-70] [South Carolina Republican Party Rules - Rule 5 (c)(5)]

April 2016 (presumably): District conventions convene to elect National Convention District Delegates according to the results of the primary. [Rule 6 (c)(6)(a)]

Saturday 7 May 2016 (presumably): The State Convention convenes to elect the At-Large National Convention District Delegates according to the results of the primary. [Section 7-9-100]

... the State Convention shall ... elect a national committeeman and national committeewoman and to elect at-large delegates ... to the National Convention. [South Carolina Republican Party Rules - RULE 7 (b)(6)]

6 June 2014: Governor Nikki Randhawa Haley (Republican) signed HB 4732. The law requires the government to fund the costs of Presidential Primaries.

10 December 2014: South Carolina Senator Vincent Sheheen (Democratic) prefiled SB 204. The bill requires that parties receiving 5% or more of the Presidential vote in the last Presidential election agree on a single date for the Presidential primaries. If the parties cannot agree, the primary would be held on (1) the second Tuesday in June or (2) on a date chosen by each party. The latter would require each party to pay for its primary.