To add a new folder select the New | Folder command from the shortcut menu, Edit | New | Folder from the main menu, click on the corresponding button or press the CTRL + I or F7 hotkeys.
Linkman will insert the new folder below the selected folder. If you want to insert the folder above the selected item, hold down the SHIFT key while executing this function.
To attach a folder as a subfolder select the New | Child folder command from the shortcut menu, Edit | New | Child folder from the main menu, or press the CTRL + . hotkey.
Linkman will attach the new folder as the last item of the selected folder. If you want to attach the folder as the first item, hold down the SHIFT key while executing this function.
When searching for multiple terms, name and keywords of the parent folder will be taken into consideration for every link inside.
You have a folder called music with several links inside. Some of these links have the keyword software. If you search for music software all of these links will be found, even if they don't possess the music keyword.
So if you want to add a keyword to several links at once, simply at the keyword to the folder that contains these links instead.
This works also with folders, to add a keyword to multiple folders at once, add it to the parent folder that contains these folders instead.