Create backend for my squarespace site

I have a squarespace site which i would like to start marketing more. Currently it has a product (advertisement) where i collect a number of fields (see sale details - attached) as part of the checkout process. I then manually use these field from the order to create a listing back on the site (see listing - attached) Currently i ask for : - Date of Sale - Time of sale - Address where sale is held - Brief sale description - Contact Number - Is your sale weather dependant? Yes/No - Do you want to hide your house number until the sale day? Yes/No. I then create a listing on a page using this info (and a map) - This is very time consuming and means that currently i can only create a set number per day. Ideally when the order is placed these fields are saved in a DB e.g. Parse where i can then check them and then approve them. They will then appear the state page i.e. VIC, NSW, SA etc without any manual intervention (except the approval). I also have a pipeline of other sites that i will require the exact same architecture for (slightly different capture fields), so looking for this project initially but if all goes well the next project will start immediately.