How can I translate all the pages & menus

Hi,
I have installed the qTranslate plugin and I don’t how translate all pages & menus using POedit, which was recommended from the theme that i bought. I already did the .po & .mo thing with POedit, but i don’t how it works.
My web is in Spanish, and I want to have it in English and French, but when you clic on the flag to change the language, the menu and pages still in Spanish.
I really appreciate your help guys!
Thanks.
Ramon