How to change the dictionary setting

I am not able to see the dictionary setting menu. I want to change the different dictionary. Can you tell me where it is or How to do it?

Click on the settings button next to the Vocabulary and Playlist tabs on the home page. The popup will appear and you will see “Reader Settings” option on the right. Under the Reader settings you will be able to change your dictionary language.
Hope this helps!

I am using the Portuguese dictionary for french, but when I try to use the English one for german it doesn’t work and I had already set it up on reader tab and also selected some on the page course tab, but every time I click on a word only the Portuguese dictionary shows up. Could you help me? =)