Language support for the events calendar plugin

I installed the events calendar plugin. Then I tried to create new event and found the language is English.

According to the guide, I upload two files “the-events-calendar-ja.mo” and “the-events-calendar-ja.po” to “/wp-content/plugins/the-events-calendar/lang” holder. Then I tried to create event.

The word “Add price”, “Add or find organizer”, “Add or find venue”, “Add event website” are still English.

Please tell me what is wrong and advice how to solve it.

Regards, Sejimo