Categories merge different columns into a folder in order to create all kinds of calculations with these columns.
To create a category, just create a new column, by following those steps: select as note type: Calculations > Category.
You will need to configure the calculation that you want to apply on this set of columns. You can also change the color of the category.
Once you have configured everything, click Save to begin creating columns for each category. Click the + button that appears next to the category name to create a new column.
By clicking on the folder icon, you will have more options, such as the ability to create a column (like the + option), edit the category and hide or show the columns this category consists of.
Depending on the type of calculation you have selected, you will see that the result of the category will be displayed one way or another. For example:
An arithmetic mean:
A weighted average:
Note: Change the weighting by going to the actions in the folder.
In this video, you will see step by step how to create categories: