How do I embed a Sign Up Form onto a PAGE within Shopify, such as my Contact Page. I am clicking the < > on that specific page and adding it, but it is not showing up?

This is the page I am trying to add it to… 
https://getthegifts.com/pages/rick-and-morty-giveaway

I am trying to run a Giveaway where I send people to my website to Fill Out an Entry Form.

I would also like to make it so they have to Follow Us on Social Media to Enter. Ideally would like this to be integrated into the form, but I could also just explain it in the text as they enter the contest, and add a link for them to do so.