With Edit|View you view the selected file. SmartSVN will checkout the file to a temporary location and open it in the specified editor, see Edit Menu for more details.
The Query menu provides commands to query for certain information from the repository.
With Log you can display the log for the currently selected directory or file. For details refer to Log.
With Annotate you can display an annotated view of a file's content. For details refer to Annotate.