The phrase "to select a winner" means to choose or pick out someone or something as the best or most deserving among a group of competitors in a contest or competition. Full definition
Others randomly select the winners from a pool of qualified applicant. (essayrepublic.com)
Independent panels of science journalists select the winners of the awards. (aaas.org)
* I - C will randomly select winners from all program entries and will facilitate fulfillment of the winning prizes (5 winners). (thefashionablehousewife.com)