Excel Help - Color coding based on start date + number of weeks

Hello,

I am working on creating a Ghantt chart on excel using the start date + number of weeks, I want to show this highlighted with a specific color based on the type of project. I have attached the spreadsheet for reference. I tried using the conditional formatting which isn't working. The attached file shows what I am hoping to automatically happen with the color coding when I add the Start Date and the number of weeks. Any suggestions? Thank you.