Build a Magento Extension

I want to create a magento 2 extension to allow users to take custom measurement per style of cloth. On the product detail page of each cloth, they'll be a button "Customize Now" where if clicked it takes users to a page watch an instructional video that teaches them how to take certain measurement (e.g waist length, sleeve length etc). After those measurement have been entered, it then saves into the user account and subsequently, the details are pre-populated for the specific clothing once user is logged into his account. In the backend, when user adds a new clothing product, he should be able to assign the specific measurement required to make that cloth so that when user checkout and purchase, the specific measurement will be matched to that clothing product. Ultimately the extension should have its rest API that can be consumed externally. I uploaded some screenshots to further explain this functionality.