You need to take a look here for details: https://simple-press.com/documentation/codex/installation/installation-information/localization/

This all works the same way as standard WordPress localisation.
Of course, it does depend on a Japanese translation having been made and I am unsure about that. On my mobile phone so hard to check at the moment…

Yellow Swordfish,

Thank you very much for your quick response.

I took a look at the link but am lost as to where exactly I am supposed to place the mo file into.

This file must be placed in the storage location defined on your system for language files.

See the forum admin > WP Integration > Storage Locations.

I downloaded the Japanese version of WordPress, so there was no need for me to do any localisation.

I am willing to help out if there isn’t a real Japanese translation since I speak both languages.

Thank you again for your help.

If you go look at the Storage Locations admin pane as it says- – then you will see three folders have been created on your web server where Simple:Press core/admin, theme and plugin ‘mo’ files get placed. And I have to say that as none of us speak Japanese any help with translations is always welcome. The translations are community driven. If you visit the translations website there is a help panel which tries to explain how it all works.

Yellow Swordfish,

Thank you again for the quick response.  I was abe to follow your instruction and install the mo file.

Unfortunately, it seems that the Japanese translation is not set at all.

I will translate them when I have time.

Thank you

AH yes – sorry to see that. 24% of core and 0% of the default theme. The theme actually supplies much more of the text you see than the core does.

Not going to help but in the next update we will be introducing a new admin tool to download and install the MO files automatically. Even less of a help if they are empty of course!