It is always a good idea to rename your steps to something meaningful in Power Query. Otherwise, you can end up with a long list of steps that will have no meaning for you in a few days, making it harder to understand what the query is doing, and even harder to edit it.
To rename a step, you just right-click on it and select rename. However, if you are creating steps that Power Query takes some time to process, either because there is a lot of data to processes, or it is downloading more data, the “Rename” option is grayed out. You can easily lose your train of thought if it is taking time to process. Furthermore, just renaming a step can cause Power Query to reprocess that step, further discouraging you from renaming it in the first place.
You don’t have to wait though. Instead of selecting the “Rename” option, select the “Properties” option at the bottom of the right-click menu.
While the query is processing, you can rename the step and provide additional information on what the step is doing. This additional text will appear in the tool-tip box when you hover over the step with your mouse, and it appears as comment text in the Advanced Editor if you are editing the M-Code directly. I usually will prefix any steps with important descriptions with an “i” so I know it has important information.
In query above, the steps have meaningful names so I know what is going on, and in the next to last step, I know there is a more detailed description that will explain to my future self why I filtered for null values.
Now you have no excuse not to rename your steps as you go.