In order to achieve the translation (or change) of a sentence or a word, you have to login in on the admin site. Then, go to Settings > Translations.
Once there, you will have to locate the corresponding template that contains the sentence or word you want to change or translate (1). After you found the template, click on the Translate button.
The next screen you will see is a list of all the sentences and words available for you to translate or change, under the Template column. The rest of the columns corresponds to the number of languages available on your site. Locate the sentence or word you wish to modify, and add the desired text on the corresponding language column. After this, click on the Save Changes on the bottom, and wait for the success alert.
Lastly, go back to the Settings > Translations list (by clicking on the Close button on the top right corner), and click on the Refresh Translations icon, in order to synchronize the new information on the front end site. Keep in mind this can take some time to be visible (2).
(1) If you can’t find the template, open a Support ticket requesting it.
(2) If you don’t see the changes after some time (usually it takes a couple of hours), clear the cache on your browser, and refresh the page. If this doesn’t work as well, open a new Support ticket informing which template and which sentence/word you modified.