Doc for translators: make it clearer how to get started

Recommended by a UX designer who reviewed this page.

wiki/src/contribute/how/translate.mdwn

@@ -22,8 +22,8 @@ Tails programs can be translated into more than 140 languages this way.
 
 ## Translate this website, including the Tails documentation
 
-To translate this website in a web browser, [[use our translation
-platform|translate/with_translation_platform]].
+[[Get started|translate/with_translation_platform]] with translating.
+this website.
 
 Please focus on translating and maintaining the
 [[core pages|contribute/l10n_tricks/core_po_files.txt]] first.