1) Create an account on the translation platform Launchpad

 

2) Once created, open the BellePoule translation web page and Log in to your newly created account if necessary:

 

3) Choose the languages you want to translate into:

 

4) Open the page of the language to translate and fill in your translations. If the item holds strange pieces of text (%d, <big>, \n), copy them as they are.