Follow the processes below:
2. Once you have an account, go to the Translation Portal and select your language.
3. At the top, you will see the drop-down menus where choose the folder and the course you will be working on.
4. All the units and lessons available for that course will be listed. Now select an item (see goals and milestones here) that needs to be translated. You can also select Untranslated on the top to see only the items that are pending translation.
5) This will bring you to a Crowdin login window. Select your language and log in. You’ll be required to join the team of your language.
6) When you see the Crowdin In-Context tool as below, you are all set to translate! Read here if you don't know how to use it.