Once an archive has been opened in ark, it can be extracted. To extract files from an archive, you can either select Extract... from the Action or by right-clicking on any file. The Extract dialog allows you to select where you will extract files to. You can also select which files to extract:
"Current" extracts the most recently selected file. If multiple files are selected, only the most recently selected one will be extracted.
"All" extracts the entire contents of the archive.
"Selected Files" extracts all the files which have been selected.
"Pattern" allows you to specify which files will be extracted, corresponding to certain patterns, ie *.txt or *.jpg. Note that you can only use one pattern at a time.
You can specify the directory to extract files to in the "Extract to:" textbox. If you want to change the default directory, in the main program window, choose Directories... on the Settings menu. Under the "Advanced" tab, you can choose some specific options depending on the archive format.