Welcome @okeygo
Take a look at the Adrestia documentation. It gives a nice overview about some components used to interact with the Cardano blockchain which is probably what you’re looking for: https://input-output-hk.github.io/adrestia
Currently everyone’s probably talking about the Shelley Haskell Testnet (HTN) which was made public a few days ago or the Incentivized Testnet (ITN) which is going to be shut down soon. You’ll find a more detailled explanation in this post: The public testnet is now open for business