Question: how to install rpm package in redhat linux 7?
Answer: Log in as root , or use the su command to change to the root user at the workstation on which you want to install the software.
Download the package you wish to install. The package will be named something like DeathStar0_42b. ... 
To install the package, enter the following command at the prompt: rpm -i DeathStar0_42b.rpm.