You can download the Finnish .mo file – which is what WordPress reads – at the bottom of the GlotPress page I linked above. Select the .mo file option from the dropdown menu, and click Export.
There are a few different places you can upload the file.
You can put it in the “languages” folder within Bushwick and it should be automatically recognized.
If you go this route, please be aware that if you click the Update button within the dashboard when there’s a new version of Bushwick, you may overwrite your language file and it will disappear, and you’ll need to restore it.
To avoid this, you can either do a manual update via FTP, being sure not to overwrite the languages folder, or you can create a child theme, so your tweaks won’t be overwritten when updating the theme. Here are some guides in case you haven’t made one before:
https://codex.www.ads-software.com/Child_Themes
https://op111.net/53/
https://vimeo.com/39023468
To use language files in a child theme you need to let the child theme know that these language files are there, by calling in the folder from your child theme’s functions.php file.
If you don’t already have a functions.php in your child theme, create one in a plain-text editor (not a rich-text editor like Word) and add this bit of code right at the top:
<?php
add_action( 'after_setup_theme', 'my_child_theme_setup' );
function my_child_theme_setup() {
load_child_theme_textdomain( 'bushwick', get_stylesheet_directory() . '/languages' );
}
If you already have a functions.php file in your child theme, add all the code above except the opening <?php tag.
This function assumes you’ve placed your .mo file in a folder called “languages” within your child theme.
Codex reference: https://codex.www.ads-software.com/Function_Reference/load_child_theme_textdomain
Let me know how it goes.