You need to have nodeJS and npm/yarn installed. Steps:
git clone https://github.com/lyra-labs/ThreeDSServer.git
cd ThreeDSServer
npm install
oryarn install
node app
The server is now running on localhost:4242
This server works in collaboration with the WebAuthPay repository, you'll need to have both server launched to use it. Refer to WebauthPay readme to use it.