Adding input fields on main.product.liquid to dawn theme product page (v.12)

[LMDN]

Hi,

I inserted a piece of code in the main.product.liquid file to have a personalized text chams in my dawn theme. I retrieve the data in my basket. Except that I have to add a submit button to send the data. It sends me all the data except the requested quantity. How can I do this more cleanly and without breaking all the code. Thank you in advance for your response