How to pass a value to the payment field?

I am having the problem of only seeing None(Manual) as an option. I only have one other field on the page, a number field that pre-populates from a registration form. I want the pre-populated field to eventually be hidden and automatically fill in the PayPal payment box so the payment amount can't be changed. https://www.jotform.com/build/70874394087165 Help is appreciated!!!

I'm not sure from where the data is passing to this field:

But, if you want to pass that value to PayPal field you need to select collect donation here:

And you need to use Form calculation field for "Total camp fees..":

Then that field will appear in the Get price from field.

Let us know if you have any further questions.

Thank you!