It may seem empty at first glance, but when you click on the Keywords tab of the Dictionaries window, you should see all the keywords imported from the Anglais (Etats Unis) dictionary.
Should you not find any Keywords content imported, you can try Dictionaries Items button Import Words from Dictionary (the last one) and choose the English dictionary again.
Now the Keywords tab is filled with imported English keywords
On Dictionaries Items tab you can start entering translations for individual original English keywords. Don’t forget to Commit the change to the dictionary by clicking Commit button (third) on the Dictionary Items toolbar.