*Please be advised, this is a guide for someone with no programming background.
Search iTunes or Android store for apps similar to your idea. Look at ones that have good reviews and see what you like about them and decide what you will do differently.
Remember if you plan on making an app it's going to cost a chunk of money, if there are fifty free apps that do something similar to yours, it won't sell well.
You are going to need some help writing the code and getting to the markets. You can either hire an app development company, just search the web or hire freelancers. I recommend elance.com or...
Guru.com You can post a vague idea for your app and freelancers will bid for the job.
When deciding which freelancer to choose: 1) look at their portfolio 2) check their reviews 3) make sure they can easily communicate with you, misunderstandings are costly.
Before you give any details to the developer you need to protect your idea and yourself. Search the web for a non compete agreement and a non disclosure agreement. There are plenty of free ones.
Send the agreements to the freelancers you like the best. Once signed the have agreed not to take your idea or share info about it with anyone else.
Make sure you decide whether you are developing for Apple, Android or both. Make sure you freelancers can handle the right operating system.
Also, make sure the give you a timeline for completion as well as offer support loading the app to the store and after its in the store in case of bugs.