The Fedora package of lcd4linux ships with a demo configuration file, shell
script and desktop file, to use lcd4linux under your normal desktop. To use
it with an actual external LCD display you need to configure it for your
specific display, and likely launch it as root. See the sample config file
included with the package, and the lcd4linux website for more info:
http://ssl.bulix.org/projects/lcd4linux/

A note about the i2c_sensors plugin, as it names suggests it was written
to get information from hardware monitoring sensors attached to the i2c bus.
But now a days machines often have hwmon sensors attached to difference
busses (such as those builtin to CPUs). The Fedora package contains a patch
to the i2c_sensors plugin to also recognize these. There still is a problem
when you have multiple sensor devices. In this case the i2c_sensors
plugin will just pick the first one (hwmon0). You can use the i2c_sensors
plugin with multiple sensor devices by explicitly setting the i2c_sensors-path
variable and specifying the hwmon device in the i2c_sensors call. Example
configuration code (note how some hwmon devices need 'hwmon#/device/...',
and others 'hwmon#/...'):

i2c_sensors-path '/sys/class/hwmon/'
Widget Temp1 {
    class 'Text'
    width 16
    align 'R'  
    prefix 'ACPI: ' 
        postfix '°C'
        precision 1
    expression i2c_sensors('hwmon0/temp1_input') / 1000.0
}

Widget Temp2 {
    class 'Text'
    width 16
    align 'R'
    prefix 'CPU1: '
        postfix '°C'
        precision 1 
    expression i2c_sensors('hwmon1/device/temp1_input') / 1000.0
}