Any ideas how to calculate timesheet?

Hi, i have a table with lost of information and have to calculate hours how mush each shift is doing.
For example RDO - Rest Day Off.
I need this:
to know how many each shift on that day is working hors.
Shifts are: Earlies 06-14, Afters 14-22, nights 22-06.
Coleagues can be doing overtime or changing hours to such situation: 04to12.
I need on that day to calculate how many hours each shift is doing. File is big, for a whole year and lots of names
it would be easier if just i would be using this file, but a problem is that format in each cell is this way:
04to14
04to08 and so on.
for an example i will attach example.
To explain: if coleague is working: 06to14 - Earlies 8hrs
if: 04to12: Nights 2hrs, Earlies 6hrs and so on.

Any ideas?