All user created translations are stored in the following folder:
"C:\Users\UserName\AppData\Roaming\wyUpdate\Languages\"
You can just extract the downloaded translations in that folder. Or, if you've created or edited a translation using the translation editor, you can submit your changes via e-mail for inclusion on this website and the next version of wyBuild. Just send the translation as an attachment in an e-mail to support@wyday.com.