[newbie] PHP on 7.2

[hohage]

Hi,
I've installed 7.2 on weekend and it's very nice.
I've got one bigger problem.
PHP4 is installed(rpm -q) but in the Apache-config file it's not adjusted and 
Apache doesn't read php or php3 files.
Where should I start to adjust my installation.
I'm afraid to make some bad mistakes if I follow one of the tutorials(i.e.on 
php.net) because they usually start from scratch(with the installation).
I thought I could manage it with Webmin but the modules didn't get activated.
Thanks.