Different lessons taught in the Youtube Tutorial Series (https://www.youtube.com/playlist?list=PLHiZ4m8vCp9PHnOIT7gd30PCBoYCpGoQM) are organized in separate branches. For example, lesson-1 source code is shared in lesson-1 branch. Just switch to a branch and see corresponding README file instruction.
Sumit Saha - sumit@learnwithsumit.com
Repository Link: https://github.com/learnwithsumit/express-js-tutorial
Youtube Channel: https://youtube.com/LearnwithSumit