Using sqRazorSample for a .NET Core Web application

I downloaded the Square Razor Sample from GIT and found it very useful to start my SQUARE Web Application payment request and processing process.

It tested successfully as is; however, I would like to extend the test and be able to either add a payment to the index.cshtml page via an input files or pass a value to the page from an invoice page for payment request that will then be applied to the ProcessPayment.cshtml.cs / OnPostAsync() / Money.Bulider() function area.

Currently there is a hard-coded value of $1.00 into the .Amount field; I would like to be able to provide that value as described above.

I tried to debug the code to follow the process but got stuck in the JScript file.
Can you please provide some guidance on a process to accomplish this task?

Thank you for your support and recommendation.