i need help please with my cake

Hello i am Jessica I am entering in a cake contest for work and i have a few questions to ask i hope you will be able to help me the theme for the contest is love and chocolate i have many ideas in my head on what i want to make and how the cake should look but, my biggest problem is i just cant get what i want on paper howcan i do this its soo hard please help me thankyou for your time Jessica