how to write 3-demensional generalized discrete choatic system ith henon map

Hello, i'm new in MATLAB and i want to write this system, i try many time but i don't get a result.please help me to write this system .

a=1.07;
b=0.3;
f(x)=[1-a*(x{1}(k))^2 ; 0 ;0 ];
A=[0 1 0;0.3 0 1;-0.3 0 0];
x=[x{1} ; x{2} ; x{3} ];
k=lenght(x); 
x(k+1)= Ax(k)+f(x(k));
figure;
plot(x,k)