When looking for help in the forum regarding questions in the query editor, you will often come across M-code snippets because the solution cannot be done using the UI alone or it was simply the most convenient way for the answerer.
If you have trouble to apply this to your existing solution, this video will show you how to do it.
If you're brand new to PowerBI and the query editor and don't know what steps in the query editor are, you should have a look at this article (and the surrounding ones) first: Query overview in Power BI Desktop
watch?v=S9xlq5KUZ60
