There are two main ways to remove unwanted columns from a data set in Power Query Editor:

1. Removing Specific Columns:

* Select the columns: Click on the header of the column(s) you want to remove. You can hold down the Ctrl key to select multiple non-consecutive columns.
* Remove Columns: Once the unwanted columns are selected, go to the "Home" tab in the Power Query Editor ribbon. Click on the "Remove Columns" button. This will permanently delete the selected columns from your data set.

2. Removing All But Selected Columns:

* Select the desired columns: Click on the header of the column(s) you want to KEEP. You can hold down the Ctrl key to select multiple desired columns.
* Expand "Remove Columns": Click on the down arrow next to the "Remove Columns" button on the "Home" tab.
* Choose "Remove Other Columns": This option will remove all columns from your data set except for the ones you specifically selected.

Additional Tips:

* Consider using the "Rename Columns" option if you want to keep a column but change its name for better clarity.
* Remember that removing columns is a permanent action. If you're unsure, it's recommended to work on a copy of your data set before making changes.