In Salesforce Setup, type 'Custom Labels' in the Quick Search.

Create a new List View to see only the labels for Email to Case Premium by clicking the 'Create New View' link.

Give the new View a name and unique name.

For the filter criteria, select 'Namespace Prefix' as the Field, 'equals' as the operator, and enter 'e2cp' as the Value. It should look like the following: 

Optionally, select fields to display, and click 'Save'.

Now when you're redirected to the list of labels for Email to Case Premium, you will see everything that can be translated into other languages.

Before translating, make sure that the languages are active via Translation Workbench.

In this example, let's translate a label for the Timeline Component. Look for 'Private Comments Filter' and click on the 'Private_Comments_Filter' link. Do not click the Edit link.

Click the 'New Local Translations / Overrides' button in the Local Translations / Overrides section of the page.

Select the desired language from the language selection in the Translation Information section of the page and enter the translated value. Then, click 'Save'.

Repeat this process for every label and every language you wish to translate Email to Case Premium into.

Here is an example of the Timeline with all labels translated into Portuguese (Brazil):

 

For assistance, please open a case by emailing e2cpremium@vicasso.com.