What do you need?
You need the .iso image file for your operating system. Here is the step by step process how you should do this.
1. Place your .iso file somewhere on your system, say /home/mine/RHEL.iso
2. mkdir -p /mypath/myName
3. mount -o loop /home/mine/RHEL.iso mypath/myName
4. do a df -h and you will see the mounted file system [Optional]
5. create a file under /etc/yum.repos.d/myName.repo and edit it the following way:
name=Red Hat Enterprise Linux
6. yum clean all
7. yum repolist -> This may give the following output:
Loaded plugins: product-id, refresh-packagekit, security, subscription-manager
Updating certificate-based repositories.
repo id repo name status
server Red Hat Enterprise Linux 3,529