From Hydrogenaudio Knowledgebase
 Properties Dialog
To activate the Properties dialog, select one or more tracks (eg. in a playlist), right-click, choose "Properties" from the context menu.
You can directly edit all metadata values (entries on the "Metadata" tab). Other information about the selected tracks - shown on the "Properties" tab - is read-only.
To commit any edits you've made to file tags, press either "OK" button (to close the dialog) or "Apply" button (to save then continue viewing/editing).
 Tools Menu
- Selection : Same as right-click menu commands for currently selected metadata fields.
- Add New Field : Adds a new metadata field with any name that you specify.
- Paste Fields : See Copy & Paste Functionality section below.
- Auto Track Number : Automatically fills Track Number and Total Tracks fields, according to original order of tracks that you've opened the Properties dialog for. Tracks placed in different folders are assumed to be separate albums and are counted separately.
- Automatically Fill Values : Allows you to automatically fill metadata values from file names / other metadata / other sources. Read more...
- Reload Info : Reloads displayed information from your files. Any unsaved edits that you've made will be lost.
- Remove Tags
- For file formats that support optional tags such as ID3 or APE, those optional tags are completey stripped.
- Any metadata or ReplayGain information is removed from the files.
 Copy & Paste Functionality
You can transfer metadata values between different fields (eg. copy track titles to comments), between different tracks or even between different sets of tracks using copy / paste functionality of the Properties dialog. Simply select one or more metadata fields that you want to operate on, right-click them and choose one of copy / paste commands.
The difference between "Paste" and "Paste Fields" commands is that "Paste" replaces currently selected fields' values with field values currently present in Windows Clipboard - regardless of names of fields that you copied before; "Paste Fields" behavior doesn't depend on current selection - it creates new fields with names and values present in Windows Clipboard - if fields with matching names already exist, they're overwritten. For an example: if you copy the "title" field, you can use the "Paste" command to put titles in the "comment" field, but the "Paste Fields" will always overwrite contents of the "title" field with copied values. "Paste Fields" is mainly intended for transferring full sets of metadata between different tracks.
To completely transfer metadata between two groups of tracks, open the Properties dialog for the source group, select all metadata fields, right-click, choose "Copy"; then open the Properties dialog for the target group, select all metadata fields, choose "Remove" and then "Paste Fields" from the right-click menu. Read more...
 Usage Tips
You can open the Properties dialog for multiple tracks - by selecting a group of tracks in a playlist then choosing "Properties" from the context menu for an example. This lets you mass-edit tags of multiple tracks at once.
Various tag manipulation commands can be accessed by selecting one or more metadata fields then right-clicking the selection.
When editing tags of multiple tracks, double-clicking a field name - or choosing "Edit" from field's right-click menu - opens a dialog where you can see and edit each track's individual values of that field. You can also select multiple fields then use the "Edit" command to open a dialog where you can conveniently edit individual per-track values of each of those fields.
If your files have empty or incorrect tags but corrent artist/title/etc information is present in file or folder names, you can automatically transfer that information to tags using the "Automatically Fill Values..." command from the Tools menu. For an example, if your file naming scheme is "artist\album [date]\nn. title", you should set source to "File Names" and pattern to "%artist%\%album% [%date%]\%tracknumber%. %title%". Read full article...
If you wish to go straight to the properties tab when opening the dialog - without additional clicking - you can hold shift while opening the dialog. This also applies to opening the dialog through keyboard shortcuts - if shift is a part of the keyboard combo used, the properties tab will be activated.