1. Use load_theme_textdomain() into a theme/functions.php or plugin file

load_theme_textdomain( 'wcoders', get_template_directory() . '/lang' );

2. Localize the content

<?php _e( 'Some string', 'framework' ); ?>

3. Create .po & .mo Files
– Create de_DE.mo & de_DE.po files with poedit.
– Translate texts from english to german & save the .po file

4. Change Your Language (wp-admin)
– Settings > General and change the “Site Language” option

//Sample .pot file
#: download-plugins-from-dashboard.php:113
msgid "Settings"
msgstr ""

#: download-plugins-from-dashboard.php:115
msgid "Unlock All"
msgstr ""

#: includes/class-alg-download-plugins-core.php:59
#: includes/class-alg-download-plugins-core.php:76
msgid "Download ZIP"
msgstr ""