Collect your supplies!!!
Trace a outline of the width of your phone onto the toilet paper roll with your pen, cut out the tracing that you created and make sure your phone fits.
Now trace the size of the toilet paper roll onto the plastic cup with your permanent marker then cut the shape out.
Now make sure the toilet paper roll fits inside the cup, if so move the cup around where you like it and stands correctly (repeat on other side).
Hot-glue the inside and outside of the plastic cups so they stay in place.
Finally decorate it how you would like (eg. Spray paint or paint) (optional)