[Installing Oracle DataBase Server 11.2.0.3 on Oracle Linux 6.3]: Official Documentation

[Installing Oracle DataBase Server 11.2.0.3.2]:

Installing Oracle DataBase 11G R2 x86 64 bit on Oracle Linux 6.3 x86 64 bit

Oracle® Database Quick Installation Guide 11g Release 2 (11.2) for Linux x86-64

http://docs.oracle.com/cd/E11882_01/install.112/e24326/toc.htm

I recommend going directly to the latest version of the document, which uses newer software versions

Link to the Oracle installation document.