How to add translations for the text key given in shell page in VBCS?

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I created an application and I wanted to add a header throughout all the pages and so I added that in shell page. while giving the text I chose translatable n gave the key as headerLink1 and the value as Help. but I couldn't find the key in app-strings.json file. The key its showing is      [[ $page.translations.shell.headerLink1 ]]. Where n how can  I translate this one?