Enter as root; and search for mysql;
i know rpm-technique is a fine thing; but under linux there are enough secrets for me, so i do some things manually;
if you cant set the admin-pass like you have written, you mysql is probably set at another path.
Mine e.g. resides under /usr/local/mysql and not under /usr/bin/
Cause ido the install manually i know where it resides :-)

To get more in contact with your system start the mc and browse tru the filesystem, looking for places ...
Just another thing, if you are new with linux, is to install the webmin-system; with this you should set your admin-pass for mysql, too - the german mirror is found at www.webmin.de; think the us at .com.
Installing is a snap; download the file; decompress it to a temp; and start the setup-file (more to know in readme)
choose all the standards to do (maybe you want the ssl-option, then you must download both parts first ... more in readme, too)

Next thing is to download the phpMyAdmin; search it at freshmeat.com or try to find it at php3.com (sorry, dont know the URLs)
Robert