how to use tfestimate

Dear all: if i got the information of the force and the response of the structure,how can i use the function tfestimate to culculate the FRF.its my first time to use this function.even if i have read the help document i still cant figure it out clearly.could you please be so kind to explain those paramater?especiallithose:noverlap,nfft,fs.i'll be sooo thankful for your kindness. [Txy,F] = tfestimate(x,y,window,noverlap,nfft,fs)