Looking for command help in Excel
 

I collect data at my work that involves 13 people; 8 on 1st shift and 5 on
2nd shift. I collect the data to monitor work productivity and trends to
help me with staffing levels. The 13 people figure varies if someone is on
vacation or absent and doesn't produce data. I am trying to implement a
template that will automatically reduce the staffing level if someone is off
or on vacation after it sorts the personnel into 1st or 2nd shift. and then
totals the input based on 1st or 2nd shift production. I have used COUNTIF,
SUMIF, IF, VLOOKUP commands and aren't getting the results I am needing. I
use a zero or blank cell to signify that the employee is off, thus reducing
the staffing level. Any suggestions on which command direction to go in for
the rest of the template would be appreciated. Trial and error on my part
hasn't gotten me very far. Thanks for looking and responding!