aiyaa zenguan broo .. dun make it too complicated for him =)
he just want to hear the song then can play it .. with some of his own style ... hahaha
not really improvising on it .... maybe improvise a lil bit here and there, but not really improvising ...
My suggestion is, keep listening and try to figure the chord.
once you get hold of the melody, try to identify the key the song are ...
like, if the song goes like , A C# D E ... E E F# E F# A ..
then from the scale, you can idenfify that it's actualy in the key of A major
A B C# D E F# G# A
then after that, figuring out the chord will be easier when you know the keys..
cuz for most pop song, they'll use diatonic chords, meaning chords from the scales up there ... =)