How to better start localizing the WordPress website

Hi, in short time we will be localizing our website. Most likely, we will be using WPML - Crowdin plugin for this (our developer says that this one should suit our needs the best).

I wanted to know the best practices aboit this. Maybe there can be issues or downsides that are not stated anywhere? For reference, I’ve read this one:

No downsides, but the most important in setting up the process is to make sure that language codes are the same on both sides (WPML and Crowdin), otherwise you’ll receive no translation (because of language code mismatch).

Here are some helpful links: