Before downvoting, please read the post.
I'm using Windows 10 v1803, and I noticed by accident that you can group tiles to a folder.
I have tiles, set their size to small, and then I dragged one ontop of the other and it formed a nice group. Grouped, they are very tiny, but you click on them to unfold them similar as how it is done in iOS mobile.
Now, you think I figured it out as you can read above on how to do it, but when I tried to do it a second time, instead of grouping, it just pushes the other icon aside and it won't group.
Eventually after crazy mouse movements I got it to keep one icon on its size, changing the border to a bigger border indicating it would group and the other icon could hover it. Dropping it did indeed create the group.
So I tried it once more, and again, I just could not get it to group. Eventually after lots of wiggling, it was allowing the group again. I must be doing something wrong because I don't think: try until you have luck, is the method Microsoft intended.
Here is what it looks like:
So, TL;DR: What is the correct way to group tiles in the Windows 10 Start Menu?