How to configure yum?
Yum is the default installation and upgrade manager for some linux distros, add the repositories to the /etc/yum.repos.d, like fedora release, freshrpms, newrpms, dag, dries, livna and atrpms etc. Repositories are precompiled or binary packages for deffrent linux distro, linux servers keep them online for the update managers to get and install them. Each repo has a release rpm file, to add repos just download and install this rpm files, these will add the repos to the /etc/yum.repos.d.
Yum (yellow dog update manager) is the defualt update manager for redhat, fedora, yellow doag, add yum repos to the /etc/yum.repos.d directory or /etc/yum.conf file, better add to the /etc/yum.repos.d, to add make a file repos_name.repo for each repositroy, here is an example of .repo file.then run the yum: yum install package_name yum update. Repos can be enabale or desable from the repositories in the /etc/yum.repos.d by changing the enabled=1 or enabled=0.