ifft implementation of ofdm using matlab

hi i have a project work and i need to implement ifft implementation of ofdm using matlab... i'm totally new to all this... my prof told me to write a matlab script...Following is the implementation required.. The signal p(t) is a supposed to be a random signal... So from the question i understand that we input some random frequencies and its ifft result is required.. Pls let me know if i am correct till this part... Next i need to add a digital waveform at the ifft's output and i am supposed to see the spectrum.. am i right??? But i dont get the part wer "lfnl=1 which gives flat response"

First generate the signal s(t) via an iFFT process from a sequence of frequency
values: f = [f0, · · · , fn−1.] Choosing n = 16, set up a matlab script that computes the
iFFT, add a pulse waveform to its output, and computes the spectrum of s(t) .Chose F such that |fn| = 1, which gives a flat frequency response.

My deadline is tomorrow and i'm really stuck on how to do it... i tried many things but couldnt get the result... can anyone pls help me with an eg wer i can build on it. Also how can i generate a random seq of frequencies to give it to ifft... so like i understand i have to first generate a random PN sequence which can be done using shift register... but how to do this in matlab.. Also the output waveform that i need to add at the ifft result is binary data... also how do i add that to see the final resulting spectrum... I have to show some simulations results too today in class before i submit it tomorrow so can anyone pls help me out...

my code was
>>x = rand(1,16); for random freq seq length 16
>>y = fft(x);
>>iy = ifft; for ifft of the random freq seq
>>plot (iy); getting the time domain result

is this the correct way.... secondly how can i add a binary output to this ifft result...