Use Per-Domain mode

Hi everyone

I have WordPress website with the qTranslate plugin and two languages.
The main language it’s English the second language it’s Germany.

I have two domains ( https://www.courses.co.uk and https://www.courses.de):

Main english domain it’s on https://www.courses.co.uk (in here I have WordPress website with two languages.)

When I use Use Pre-Path Mode (Default, puts /en/ in front of URL). SEO friendly. Everything it’s wortking fine. After change language I have
https://www.courses.co.uk for english version and https://www.courses.co.uk/de/ for Germany language.

The germany domain what I have it’s https://www.courses.de

I would like to have option when you change language to germany you have different domain https://www.courses.de and when you change language to English you have https://www.courses.co.uk

How can I do that?

I founded option in qTranslate “Use Per-Domain mode: specify separate user-defined domain for each language.” where I paste this both domains.
But when I change to different language (Germany) it’s going to empty folder on my server where I have this domain.

What else I need to do with domain https://www.courses.de ??
Do I need to do any pointing domain https://www.courses.de to https://www.courses.co.uk or do some changes on DNS? Or maybe add some code in .httaccess?

Any one can help me with that?