ACF field

I’m new with the plugin, coming from qtranslate.
Everything works fine (specially with the REST API, the reason why I abandoned qtranslate)

I’m just having trouble with ACF PRO field.
I can’t see any documentation.

It must be trivial but how can I add an ACF field to be translated?
the field is only displayed on the main language.

It’s a simple text field to be displayed on all post

I’ve tried to add it on the wpm-config.json :
{
“post_fields”: {
“mltext”: {}
}
}

or “acf-field_5a840b67e9737”: {} or “field_5a840b67e9737”: {}

But it still be displayed only on the English tab of the post

I must be missing something obvious!

I’m using
WP version 4.9.4
ACF PRO Version 5.6.8
WP Multilang Version 2.1.12

thank you, great plugin!