How to construct a signal using a funtion

I have to construct a signal having 1) N points 2)freqsin - these are the sinosoid frequences 3)ampl - Amplitude of sinusoid

i tried [x t] = signal(freqsin,ampl,N) but it gives an error saying the signal function is undefined. I thought matlab has an inbuilt function called signals

Kindly help Thx