You can arrange your magazines in your account in so called "Collections" and "Sections".
Collections can contain multiple sections and sections can contain multiple magazines.
Click here to learn how you can create collections and sections.
After you created some collections and sections you can put your magazines in them. Learn how to do that here
Go to "My Publications".
Click on "Collections" then "Open Collection".
Click on "Edit" and make sure the arrangement is set to "manually"
Now click and hold the magazine you want to arrange and "drop" it where you want it to be
Save the settings by clicking on "Done"