Start with your domain model and only once that is ok, create your registration-form. You might consider this data modelling course.
When your most logic description of your model does not match with the reality, like in “time-sheet object can contain only one data-line in each attribute” is not coherent with “ weekly time sheets for each employee“ you will have a hard time creating the form. It is an indication that you need to reconsider the timesheet entity.
In real life a timesheet covers a certain period of time and has multiple timelimes, possibly more than one per day for different projects, projecttasks or persons and of course every day a new one. So you have a timesheet-entity and a timeline-entity with a 1-* relation. The timesheet can even be non-persistent, since it only groups some timelines. Maybe by week if the employees need to register their hours at the end of the week at latest, Or by month because the company bills per month. The entity timeline has a date, a person and a project as key, maybe also a task as well. As attribute of course the number of hours and optionally a start- and endtime.
Something like this, where Realization is your Timeline. As you see, no Timesheet,
Appreciate your help Tim.