Where is the .mo file for Select Language At Signup plugins

Dear Sir,

After I installed Select Language At Signup, I have not see a select language option is added to sign up page.

Usage 3.
Create a new language folder on your hard drive and add all the .mo file to your language folder.

Where is the .mo file ?

Usage 8,
Install the Select Language At Signup plugin.
I need all the language, how I should do.

I drag it into
/wp-content/signup-language
Is right?
Thank you!
https://premium.wpmudev.org/project/select-language-at-signup/