RPM = Redhat Package Manager
I install from a command. To install a rpm type file, you would issue a command like this:
rpm -i name-of-file.rpm
man rpm for more options and details. also search this site as its discussed and asked all the time.
Most likely you have a winmodem, try going to that site or maybe linmodems.org for details on getting that modem to work.
Some great sites for your sound, try www.opensound.com