critical to the sites continued to work, or not ?
and you to learn, or that somehow worked, but without Apache?
manuals fully online, for example
or Google install lemp centos 6.4
the fun starts when you want nginx with support for http2 and php7 simultaneously with php5 - there is already a need to Tinker.
there is still this option:
but it's not for everybody - yet initially, it's best to be able to configure.