TOPIC: Extra Coding Help

Ok ... DT Donate is not quite what I wanted, but still far better than anything else out there. Apparently you can have only ONE donation of any amount. My fault for not paying attention.

What I need is this ... the ability for a donor to manually enter his donation amount into one or more categories and have those categories totaled.

I think I can make DT Donate work but need a little help with some coding. I can create custom fields for each of the categories. Even though this appears on the screen with the donors name and address, I can live with that.

What I need to be able to do is total up each of the custom fields and plug that amount into the User-Input field on the next step. Can anyone tell me what file(s) I need to work with? Any coding suggestions would be appreciate.

Thank!
JCoulter