How to change column width and margin in the Layout Grid?

How can I set the Layout Grid – Column width and margin between the columns? I use Mendix 8.7.0, but I don’t see Column options described there:  
1 answers

When you create a new page choose Blank at the left side and you will see a blank page. If you choose that one you have an empty page with a layout grid column. With right click you can add a column to the left or to the right.

You can also use add widget and type in grid. You will then see the option Layout grid. If you choose that one it will ask you how many columns you need.