For ode45:
The general syntax is ode45('func', [tmin,tmax], [x0, y0]),< where you have another piece of code saved as func.m, tmin and tmax are the minimum and maximum values of time you want, and [x0, y0] are the initial conditions at tmin. Don't forget the quotes around func. It's also possible to do this for systems of dimensions higher and 2.
While the command above will give you a plot, you can extract the numerical data via [t,vars] = ode45('func', [tmin,tmax], [x0, y0]). This will give you a list whose elements are of the form [tn, [xn, yn]]. Then you can do plot(t,x(:,1)) to just plot the x's versus time, for example.
The script func.m should define a function that takes t and vars as input, where vars is a list containing the current values of your variables, and returns another list containing the current values of the derivatives of your variables.
The example I did in class is available here. Try downloading this and running ode45('predatorprey', [0, 60], [250, 30]).