How do I update YUM repositories? [closed]

I am very, very new to all this so baby steps please if helping is appreciated.

I am trying to connect to the following repository so I can update my YUM packages: http://repo.webtatic.com/yum/centos/5/SRPMS/

honestly I have no idea how to do that from SSH though - any guidance is very appreciative.

The instructions are listed at: http://www.webtatic.com/projects/yum-repository/

rpm -ivh http://repo.webtatic.com/yum/centos/5/`uname -i`/webtatic-release-5-0.noarch.rpm

yum clean metadata

Taken from "man yum" ?clean

CLEAN OPTIONS

  yum clean expire-cache
         Eliminate  the local data saying when the metadata and mirrorlists were downloaded for each repo. This means yum will revalidate the cache for each repo. next time it is used. However if the cache is still valid, nothing significant was deleted.

  yum clean packages
         Eliminate any cached packages from the system.  Note that packages are not automatically deleted after they are downloaded.

  yum clean headers
         Eliminate all of the header files, which old versions of yum used for dependency resolution.

  yum clean metadata
         Eliminate all of the files which yum uses to determine the remote availability of packages. Using this option will force yum to download all the metadata the next time it is run.

  yum clean dbcache
         Eliminate the sqlite cache used for faster access to metadata.  Using this option will force yum to download the sqlite metadata the next time it is run, or recreate the sqlite  metadata  if using an older repo.

  yum clean rpmdb
         Eliminate any cached data from the local rpmdb.

  yum clean plugins
         Tell any enabled plugins to eliminate their cached data.

  yum clean all
         Does  all  of  the  above.  As a convenience, if this command does not result in a completely empty cache due to the restrictions outlined at the beginning of this section, a message will be printed, saying how much disk space can be reclaimed by cleaning the remaining repos manually.  For this purpose, a repo is considered clean when its disk usage doesn't exceed 64KB (that  is to account for directory entries and tiny metadata files such as "productid" that are never cleaned).