I am sure there are guides to this in the wiki but i feel generous so here goes

This is obviously with the English version as I don't speak Egyption :
Open LFS
Go into Options -> Controls
Make sure "wheel/js" is selected at the top
Go to "Axes/ff"
Press your throttle pedal down, watching on the left which axis moves
Click the word "throttle" and then select the axis that moved in the above step
Do the same for your brake and clutch.
For me throttle axis 1, brake axis 2, clutch axis 4.
Make sure that for the pedal axis that it says "invert 1" and not "invert 0"