totaalweek:
00:00 notation is gone
=ALS(SOM($L$3:L3)=0;"";SOM($L$3:L3))

On week 2:
Only if I do work on Mondays for 8:00 hrs
its counts thru vryday

Monday 7:30 to 16:00 = 8:00 hours
Tuesday free - box must be empty (no 00:00)
Wednesday free - box must be empty (no 00:00)
Thursday - box must be empty (no 00:00)
Friday - box must be empty (no 00:00)
Yellow box: is total hours worked. (8:00)

you understand it a little?