Hi Cecilie,
You don't have to upload any information into any of the layers this week. You will have to build flow diagrams with the flow diagram builder for the materials that the cities are in charge of. To select and edit a material of that list, click on "manage blocks". The videos explain the use of those value chains and how to build them. Let me know if you still have questions after you have seen the videos of M3.
Next week, we will take the flow diagrams of ALL those sector materials and export the NACE codes. Only then will you need to check which NACE codes apply to your city and the GDP, GVA, actors, employees for each code, per all 11 construction material.
Good luck!