In your old mail system, you might have organized your messages in folders. If you had a lot of different categories of messages, you probably nested your folders in a hierarchy. That way, you could find a message by navigating and opening your folders.
In Gmail, you can do the same thing. Only instead of putting messages in folders, you associate your messages with labels. Labels are actually more powerful than folders because a single message can be associated with more than one label. (By contrast, we bet that in your old system you could put a message in only one folder!) As a result, in Gmail, you can find a message based on any of its associated labels. This way you have options to navigate by search or by expanding the hierarchy of labels you’ve created.
To begin, let's create a top-level, or parent, label. In our case, we'll create a label named Projects, since we have a lot of different projects to associate messages with.
One way to create a label is to click the More link in your label list (1). The list expands, where you can click Create new label (2). A window then pops up where you can type the name of your label (3). Since it's a parent label, don't check the "Nest label under” box.
Now let's create a label nested under Projects. Again, you can do this in a few ways, but easiest is to point at the Projects label and click the down-arrow that appears (1). This opens a menu where you can choose Add sublabel (2). A window pops up where you type the name of the label (3). Since we're making a sublabel, Gmail has already selected the option to nest the label under Projects.
Nest an existing label
Creating nested labels is easy enough. But how do you nest an existing label? Let's say you want to nest the Hanes label under Projects. Simply point at the Hanes label and click its down arrow (1). Then click Edit (2). In the window that opens, check the Nest label under box and choose Projects from the list (3).
Or as a shortcut, simply type Projects/Hanes and Gmail will nest the Hanes label in Projects for you:
You can nest as many labels as you want, and down to any number of levels. Then expand and collapse your labels by clicking the arrow at the left of the label. Here, we've nested a few labels under Projects, then nested a few more for the Hanes project.
You can also create and manage labels by going to your Gmail Settings and opening the Labels tab. There you can create and nest labels, rearrange them, and much more!