You might not want to use any of the NSA links posted there
Or some better, more or less up to date, documentation.
Other than understanding file and process context. the single most important things to know, are:
Now you can test, and use audit2why to understand what's wrong. Use audit2allow to create a SELinux module, but please check what it allows. you might allow an NSA backdoor to work
The setenforce 0 will actually give you all the gory details that would be encountered after fixing the first problem, or the next, or the one after that.
Create a rule for the filecontext of path /usr/local/share/roundcubemail/temp:
semanage fcontext --add --type httpd_sys_rw_content_t "/usr/local/share/roundcubemail/temp(/.*)?"
restorecon -R /usr/local/share/roundcubemail/temp
Widget Connector url https://www.youtube.com/watch?v=_WOKRaM-HI4