To professionally translate the theme, first you need to:
Then, go to WPML->Theme and plugins localization.
Click on the button to translate the strings in the theme and you will arrive to the String translation page, showing only the theme’s texts.
You can choose individual strings to translate, or translate all the strings that are missing translation. You can also translate strings in theme options, widgets, WordPress fields (like tagline) and plugins. Change the context at the top of the page to translate these.
Select the strings you want to send to translation as well as the target language and click on Add to translation basket. From there you can send the basket items to translation.