edit f
[t,y]=eul('f',[0,1],1,0.2);
[t,y]
plot(t,y,'o')
hold on
ezplot('t+exp(-t)',[0,1,1,1.4])
[t1,y1]=eul('f',[0,1],1,0.1);
[t1,y1]
plot(t1,y1,'ro')
[t2,y2]=Heun('f',[0,1],1,0.1);
[t2,y2]
[t3,y3]=rk4('f',[0,1],1,0.1);
[t3,y3]

Remember help with any command gives a summary of the command and options, eg.
help plot
help ezplot
help rk4

also try the command lookfor  (see help lookfor).