Build three stage checkout website - Magento

Hello, I am looking for a ecommerce website created on magneto ideally if possible. I have the basic site hosted and fresh from installing on the hosting server. This will primarily be a webdesign job, I am looking for the website to be created so that I can guide the customer through a three stage website. Please see the attached for an example of the home page. The homepage will act as a guide, with a click through to a 'Create your's now' button. This will then step through to a page where the customer can select from 5 different products, with descriptions for each one if clicked into. However I wish this description to be a pop up so that it doesn't complicate the selection page. When selected there will be a button showing which states, 'Choose your size ' Again - a selection page same as before comes up ,this time with the sizes 3 options. 1kg, 2.5kg or 5kg. Again - then a button to proceed to the 'Choose your flavours' page. On this page there will a variety of around 500 flavours. Based on the previous selection on product size it will give the customer the option to choose a number of flavours to flavour their product. These will be - 1kg = 2 Flavour Variants 2.5kg - 5 Flavour Variants 5kg = 10 flavour Variants. At the top it will say ' Choose 2/5/10 flavours depending on the previous size choice. I am looking for all the flavours to be in a grid so the user can scroll through. When the customer has selected their limit of flavour it will then prompt to either proceed or amend flavours. Proceeding will take through to a one page checkout. Happy to use Magento inbuilt payment functioning with the bolt on one page checkout options in the magento store. If it can be built on a seo optimised base theme or you can optimise it, I am happy with either. Apologies if this brief is confusing, please contact me for more details. In summary I am looking for a three step ordering system with numerous variants at each stage which condition the future options. Not sure how easily this can be built on the current magento variant systems, but staying as close to core system will be useful as it will keep the back end simple. Regards,