In the first combo you can choose the source language
In the first edit text you can write text you want to trnaslate.
The "Voice" button active voice recognition and acquire text to translate.
In the second combo you can choose the destination language.
"Translate" button translate your text, if network is active.
Last check field active your device for reading translated text.
Long press on translated text you can see the translated text on full screen (rif.2)