The way I do it is I created a folder on my computer where I put all my characters and their stuff. Then I go to "Edit > Preferences > Content Tab > Content Directory Manager... > DAZ Studio Formats" right click and add your folder to "DAZ Studio Formats".

When that's done go to your "Content Library" Tab in the main application view and you should find the name of your folder in the "DAZ Studio Formats" at the very top of your menu list.

After that go to a "Presets" folder in your folder you named. In there you should see some folders in there like Characters, Light, Materials, Wearables, Render Settings, Poses, Etc. Any folder you add in your folder in Explorer will also appear in there.
Just go to the folder you want to save your characters in and save them there by pressing the + sign at the bottom of the "Content Library" and select "Character Preset...".

The other folders should be self explanatory and the option to save should are in the + sign menu.