I need a calculated fields form in wordpress. (Excel 2 Wordpress)

Hi,

Please find the requirement overview below:
- I created a tool called the calorie calculator (http://www.marcdressen.com/?ms_song=calorie-calculator) to create custom meal plans, calorie intake and macro nutrient intake.
- I'm launching all new fitness product in jan 2016 called the www.12weekathlete.com
- Part of this program will be a nutritional part including the calculation of individual calories.
- I will use shopify as the eCommerce platform

Now here is what I need (Customer Flow):
1. The customer should purchase the product via shopify or any other eCommerce platform.
2. After committing to the purchase >> a site/questionnaire should appear asking for specific personal details relevant to the product. maybe using something like (https://wordpress.org/plugins/calculated-fields-form/screenshots/)
3. This personal informaiton will be used to then create a individual pdf for the individual to download.

I hope this is clear.

Please let me know if you can help and also provide relevant experience / portfolio.

Thank you,
Marc