YUL is a low level language close to bare metal in contrary to Vyper or Solidity languages that are high level languages.
We create a smart contract that is just adding one number
We create a build folder, a test folder and a script folder.
To compile the contract :
node compile/compile.js
To deploy the contract :
node scripts/deploy.js
To test the contract :
node test/PureYul.test.js
As a reference, the original smart contract coded in solidity is illustrated with solidity.svg.