It is always preferable to chill the cake layers for a few hours before assembling. This enables the cake layers to hold their shape and texture while assembling.
Arrange all three layers on a flat work surface.
With the help of the two cutters, carefully slice the cake layers into a 6 inch and a 3 inch ring/ circles.
Now carefully, rearrange the rings of cake. Such that the colors alternate.
Lets begin assembling the cake.
Keep one (mixed) layer on the cake stand and spread the frosting. Smooth it out and place the second (mixed) cake layer on top. Repeat for all three layers.
Frost the cake with the frosting. Decorate as per your choice!