Yay!
They eat microscopic food so I'm thinking those prawn eggs would be too big.
I use my fingers to collect the eggs. Java moss is a good idea.
It's actually the infusoria that they eat when they are just hatched that takes longer. If you can get your hands on the supplies, the brine shrimp will only take a couple days. You get those going after egg collection. The infusoria however would ideally be going a few weeks prior to egg collection. I would completely read up on that and get it started today. If you don't have any infusoria ready, you need to have the newly hatched tads in an environment with lots of plants. Java moss, hornwort, and duckweed are all good choices.