create input form from dropdown list and save data in table

Hi all,

I need to create some kind of input form based on attached table.
The table shows different departments. Each department can have different projects.

What I need to have is (on a separate sheet) a input form, whereby a person can first select the department (row 2 in the "Hours" tab) from a dropdown list.
Depending on the department, another dropdown list should appear whereby only the relevant projects (row 3 in the "Hours" tab) from that department can be choosen.
Then a field where the date can be entered and finally a field where the person can enter the number of hours spend on that project.

The table on the "Hours" tab should then update the relevant cell. E.g. when I choose Department 1, I can choose either Project 1, 2 or 3.
When I choose Project 1, enter the date of October 28th and fill in 5, it should update the "Hours" tab in cell D5 with 5.

It sounds pretty straight forward, but I have no clue on how to achieve this.... Therefore I'm hoping that your expertise can help me out here.

Thanks!!!
Peter
hour registration.xlsx

partially solved, creating new thread with current question...