I tried to follow the advice in websiteforstudents.com/install-limesurve...mariadb-and-php-7-2/ , however I am stuck when trying to download LimeSurvey CMS from download.limesurvey.org/latest-stable-re...3.14.3+180809.tar.gz . I know that the version is old and would like to install a newer version, but I can't find an installation file.

Could it be that this is not possible anymore? Are there different solutions?

Hi,
you are right.
At the moment the download page is a bit difficult to find.
On the start page "limesurvey.org" scroll down.
There is "Open Source / Community". Click.
Now you find the "Download" page with the latest releases: The stable 3.x. and the still unstable 4.x

[url] community.limesurvey.org/downloads/ [/url]
Joffm