Language to write content for my website

The theme pourchase included multilanguage….you made l’installation of the theme (included with the purchase).
Watch the document suggested for you, the language part you told me, but I do not understand….
You told me : I need buy a pluging (VPML) for it and made installation….
So, if this is not included, where buy the pluging VPML? How much? If you install it me?
Remember: I want to writte in Spanish, and that people can read it in other language if they want.
Thanks.