Launchpad is not the Applications folder. The instructions should show you how to move Launchpad icons into folder by dragging one app on top of another. You can then add more apps to the folder.
Hi Barney, Thanks for the reply. I do understand your point as Launchpad is not the Application folder and Launchpad create Aliases, as BobHarris said, whatever in Application Folder. right ? But I found it does not create Aliases of everything in Application folder and as far as I have seen, somehow, developers have a way to access the Launchpad database. Because when I install Adobe Suite, the Adobe Suite installer create two to three folders, group, in Launchpad. One of them is named "Other" which we already have in Launch with Apple application from Activities Folder.
Is the system decide the name "Other" and put those alias into same group ? or developers modified the database to put those aliases in the "Other" group ? Also create another group called "Adobe illustrator" with just 3 scripts file but the rest are out without group. Same goes to Maxon, BorisFX, Houdini, Autodesk, Pixel Film Studio.

Is the system decide and create a group with developer name or developers modified the database to create their own group ? The Downloads (Other) is appeared when I install Maxon.