how can I determine amplitude, phase and frequecy in FFT?

The signal I have attached like this. If I give the L value is equal to length of time, the value is 1501. But frequency matrix is coming 1 by 751. So for this plotting issue is coming. Phase part i am unable to do.

So, what will be the correct code for frequeency, amplitude and phase?

I have tried to do it with this code

Time= 0:2:3000;

tt=time;

ss=signal;

Ts = mean(diff(tt)); % sampling time

Fs=500; %sampling frequency

Fn=Fs/2;

L=length(tt);

Y=fft(ss);

P_amp=abs(Y/L);

f=Fs*(0:(L/2))/L;

[KALYAN ACHARJYA]

Check here, or here it may helps.