Much like in Excel, sorting lets you choose which columns you want to sort the data by (alphabetically).
This can be very useful if you are looking to change how data is grouped for ease of readability.
Default Sorting
Let's start off with a fresh report, a 'Sales by Product Variant' report:
Most reports have a default sort option to define how the data is sorted. You can notice this via the arrow in the column header like so:

Ascending vs Descending
Right away, you can tell from the direction of the arrow that all of the data is sorted by 'Gross sales', descending from Highest to Lowest.
In other words, this report shows me which products had the most sales in the last 30 days.
If I changed the header to be ascending from Lowest to Highest (which we'll cover in a moment), you can see that the data would instead look like this:
Sort Levels
Much like in Excel, you can have multiple Sort levels to decide how you want your data sorted.
Once you do so, a number will appear by each arrow so you can tell what level each sort is.
Essentially this comes down to something like "Sort by X, THEN Sort by Y (etc)".
For example, let's say I wanted this report to be sorted by
Yellow - Product title (Ascending, so A-Z) and then
Green - Variant Title (Descending, so Z-A - essentially grouping all the similarly named Variant sizes together into Small, Medium, Large) and then
Red - Gross Sales (Ascending, so High to Low)
The end result would look like this:
As you can see, grouping the data like this makes it much easier to view the data and helps me get an alphabetized list of how products are selling.
Adding, Removing, and Changing the Sort
So now that we know how the Sort Options work, let's go through how to add them to a report.
Each of the sort options essentially runs on a 'clickable-cycle'.
In other words, every time you click on the header, it cycles to the next stage in the following list:
No Sort -> Sort Ascending -> Sort Descending -> No Sort... (etc)
Changing Sort Levels
If you are planning on using multiple Sort Levels, you can use this process of adding and removing Sorts to change the different Sort Levels.
First, let's start with that basic 'Sales by Product Variant' report and have it sorted by Product Title, then by Gross Sales:
Now suppose I want to change it to sort by Gross Sales first, then product title.
First, we need to click through to remove the sorts from the report. It's always best to start from a clean slate.
Then, we click Gross Sales (twice, to make it descending).
Then we click Product title (again, twice) to add the next level sort:
Basically the rule-of-thumb is - Add your 1st Sort Option first, then your 2nd, then your 3rd (etc).
This makes it easiest to track at every step, so you can make sure data is being grouped the way you want.
Note that if you removed a lower Sort Level, then the next in line would become the new first Sort Level (e.g. removing it from Gross Sales would make Product Title the first sort).
And that's it!
For other articles in our Basic Guides series, check out our main section here.