How to make folders weighted

I am sure this is very simple but I have not figured it out.
I want to set up my grade book so
Homework folder 10 %
Quizzes 30%
Etc.. so each column will be simple number grade and the app will do the magic math and I will have a total grade.
How do I do this??
Many thanks

Hello Kathryn,
From the gradebook view > Add column > Calculation > Weighted average.
Tap on the headers of the folders you'd like to take into account and assign its weight

Thank you for your reply. When I select weighted average for the folder it shows me all the columns in that folder with a percentage box.
So if I had 3 assignments I can make each worth 3.3% to equal 10% But what I want is for the folder to be 10% and then add in the assignments with a number grade. I won't know how many assignments there will be exactly. But the total is 10% of the final grade. I hope this makes sense.

I know that I should not have to adjust the value each time I add an assignment.

You do not have to change the weights of the columns inside the folder. The default values will do and it will automatically calculate an average between all the assignments you put inside.

The 10% must be specified in the calculation above those assignments, the one where you pick which columns or folders to take into account.

In the add column > Calculation > Weighted average option you will select which folders to take into account and assign its weight. This weight does not depend on how many columns are inside the assignments folder.

The biology sample class shows a similar configuration in the 'Average' column. Here is a screenshot