I have been banging my head at building and installing/running the cardano-node and plutus source code repos,
and though the playgrounds run, I have not been able to figure out yet, how to build a complete application
using marlowe contracts (complete stack: testnet - cardano-node with testnet connection - backend server (probably haskell based) - frontend
You can’t do it yet, but we are working on that.
What you can do now is write and test your Marlowe contracts using Marlowe Playground, so when Plutus is out you’re halfway there.