A few things
1) RHEL is not free
there is a "free" version but you can not install any new software on it .There are NO security updates .The main way to install software "yum" dose not work
so buy a license - RHEL6 is the current
or use the FREE community version CentOS
however rhel/cent are not designed for laptops .
They will run on most but not all laptops and somethings like the sound and the microphone might need to be manually set up
CentOS and laptops are not a good mix , unless you have years of working experience .
2) the oracle database ???
unless you MUST use it for a program there is a better and FREE one MySQL
mysql is also installed in most linux distros
CentOS has mysql DB, & Apache -web server installed by default ( just not turned on )
For a new user i would recommend that you install Ubuntu or Mint .
Both are designed for ease of use by new users
has links to them
also the Ubuntu forum is a very good place to learn things .
also for learning some of the basics
search this forum there are links to online books and tutorials all over the place
like this one - a bit old but it covers the basics for the command line - terminal , text only ( bash, csh,zsh)
but one thing is very important
READ the documentation for what ever distro you install
both Ubuntu and Mint are very well documented