At the console, type:
This will print to the screen the help file for the "tar" program in a format you can easily read - the -zxvf options will be listed, and reading the help files is the best way to learn.
You can also type:
at the console, and this will display a MANual page for tar.
Remember these options:
Displays the programs help menu 99% of the time.
where PROGRAM is the name of your desired program without the brackets, so you would type "man tar" as above.
Hope this is clear enough!