C1 Transit Visa Application Question

Hello everyone. I'm planning to have a vacation in a country in South America hopefully by my birthmonth or ber months, and this is my first international travel in a US country. I have some questions for the transit visa application.

My questions are: 1. In the application site for DS-160 there is a final question that says "location for visa application" or something. Am I supposed to indicate the country which I'll actually visit, or the country where the lay-over will happen? 2. I've seen different answers so am I supposed to but my round-trip ticket first, or purchase it only when my visa has been approved? 3. Am I required to have a show money for this vacation?

I would appreciate additional things I need to know when applying too. Thank you very much 🥺