Question: how to use DEplot

Firstly applogies for if this question has been asked before.

I am trying to plot a simple epidemic model for where I can change the rates.

My equations are:

de1:= diff(X(t),t)=a*X(t).Y(t);

de2:=diff(Y(t),t)=a*X(t).Y(t) - b*Y(t);

where X is susceptibles and Y is infected.

I would like to be able to produce a graph with the susceptible and infected plotted. Where i can change the initial conditions of X(0) and Y(0) using sliders and also be able to change the rates of a and b using sliders.

Your help would be greatly appreciated. So far I have managed to plot the graph by only setting initial conditions, however i would like a more general solution where i can change the number of susceptibles and infected and the rates.

Thanks