Web Based Calendar App Needed

As a business we supply products to different online channels, and the websites sell the product for a week, and then another website sells it for another week. However only one website can run the product at once. Therefore we need a simple colour coded online calendar that our sales team can edit and show the weeks that are booked for each product. The calendar needs to show: 1. The product (which we need to be able to add and remove) 2. The website we are selling it on (which we need to be able to add and remove) 3. The weeks it is running on each website (which we need to be able to set) We need 2 levels of permissions: 1. That our sales team can log in to change and set the information. 2. A view that the websites can see (but can't edit) so they can see which weeks are booked. It needs to be very simple to use but have an attractive UI so that our sales team and the websites we are supplying can easily see what products are running and when. Please let me know your thoughts on the above and we are open to any suggestions. Please read the project first and write the word "Understood". Also write your steps and suggestions to complete the project with a short description of what you understood.