Po file editing
Some Basics
A .po file is a plain text file.
if you are not familiar with the PO format, gettext documentation is worth reading, especially sections dedicated to this format, e.g. by running:
info -n '(gettext)PO Files' info -n '(gettext)Header Entry'
Note down the string that you wish to translate, translate it and then replace it as shown in the example below. For example
Before
#. Type: text #. Description #: ../main-menu.templates:3 msgid "Debian installer main menu" msgstr ""
After
#. Type: text #. Description #: ../main-menu.templates:3 msgid "Debian installer main menu" msgstr ""