What is the process of how to separate diethyl ether, ethanol and water?

You will have a 2-phase mixture - The upper phase will be mainly diethyl ethere and the lower phase aqueous (assuming approximately equal amounts of all three). A separatory funnel can be used to obtain water-saturated diethyl ether as the liquid left after draining out the lower aqueous ethanol layer. The ether can be dried using Drierite, anhydrous calcium sulfate, etc.

The lower layer can be distilled to obtain an azeotrope of approximately 95% ethanol 5% water. Further purification is complicated involving ternary azeotropes (ethanol, benzene and water), etc. Freezing can also be used to isolate more pure ethanol.

A low-tech solution (no pun intended) woudl be to allow the ether to evaporate; As the distillation of diethyl ether above, this would yield aqueous ethanol