[Wien] relativistic quantum number

[yxl at email.jlu.edu.cn]

Dear users,
   I'm a biggner,I want to ask a quenstion about relativistic quantum number,how the spin quantum number is defined ? Are +1 and -1 mean spin up and down?In s state there is only one relativistic quantum mumber -1,but in s state occupied numbers is two. I'm in confusion,Please help me! Thanks a lot.
                                              hongxia