Sometimes you can have tables in your tabular data model with too many columns. You can organise them using display folders like in the example below.
You can create a display folder by editing the properties of columns while working on your Tabular project in Visual Studio.
In your tabular project you can bring up the properties pane by going to View > Properties Window or hitting the F4 key.
Then either in Grid view or Diagram view highlight the column you want and edit the Display Folder property like below.
You can also have a column display in multiple folders by separating the folder names with a semi colon Fiscal;Finance Dates. Or you can put a column in sub folders by using a backslash Fiscal\Months