Custom Column Help

Can anyone help me to figure out how to create a new column in Power Query Editor that would take a Sum of Rated_Hours based on Request Week. For Example, 10/29/2023 would have a column next to it reading 37.6. 

I would then want to remove duplicates so I have 1 row that shows 10/29/23 and 37.6 total rated hours. Which in turn would allow me to create a one-many relationship with another table I already have established.