I need help with 2-step Adams-Moulton method please!?

Hey Everyone I could really use some help answering this question as I have tried to answer it several times and I can't seem to understand exactly what to do. so if someone could please show me a step by step calculation(Bow)

The initial value problem y'= f(x,y), y(X0)=Y0 is to be solved numerically using the 2-step Adams-Moulton method

Yi+1 - Yi = h/12 [ (5 Fi+1) + (8 Fi - Fi -1)

where Fi= f(x, y) . Find the local truncation error of this method and hence determine its order.

Thanks for your help everyone, much appreciated :-)