how would i write script to graph the 't' and 'y' values?

figure;
load('ALL_DATA.mat','Box40');
subplot(3,1,1);
plot();
legend('t','y');
title('Testbox');

Answer 1

[KSSV]

Read about plot function.

plot(t,y);
xlabel('t')
ylabel('y')

Answer 2

[VBBV]

figure;
load('ALL_DATA.mat','Box40');
subplot(3,1,1);
% use the struct name to access the t & y  variables
plot(Box40.t,Box40.y);
legend('t','y');
title('Testbox');