[Resolved] Language URL format options

Problem:
You are using WPML to translate your site from German to English and have set up 'Different languages in directories'. However, the German homepage incorrectly redirects to domain.de/de/ instead of just domain.de, and deactivating WPML plugins resulted in the URL becoming domain.de/de/de/de. Additionally, you inquired about the necessity of changing internal absolute links to relative links and requested a checklist for starting with WPML.
Solution:
First, ensure that in WPML > Languages, the option 'use a directory for the default language' is not active. This setting should prevent the default language (German in your case) from being placed under a subdirectory, thus keeping the main domain clean (domain.de).
Regarding the internal links, WPML manages these when you switch languages in the backend, so there is no need to change them to relative links.
While we do not have a specific checklist for starting with WPML, we do offer a Getting Started guide which can assist you in setting up WPML correctly.

If this solution does not resolve your issue or seems outdated, we recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. Should you need further assistance, please do not hesitate to open a new support ticket at WPML support forum.