Is there a guide for dummies out there how to install XE in CentOS 6.5
Oracle&reg; Database Express Edition where you can see that your OS is not in the list of supported OSes...
...but you may try...
Not sure which kind of dummie you need a manual for (first time oracle user, centos newby, never used a computer ) ?
There are plenty installation guides (just google "oracle 11g XE centos install guide") out there for earlier versions , so centos 5 or centos < 6.5 (without VM).
I think oracle never certifies against centos but it does for Redhat which is technically similar. If you need a free OS you might also want to check out Oracle Linux which is supported).
Installation should be identical for 6.5 compared to 5 or earlier 6 releases, maybe some libraries will be more recent but that should be no problem ( be sure to use yum for installing packages/libraries, will save you a lot of problems ).
11G XE runs great on Centos 6.5 but make sure you are running the 64 bits version ( not sure if there even still is a 32 bits but just in case ).
If you run into problems with the libraries you need, let me know, I can make a list of all installed packages on my system.