@sunilyadav84 That approach works well if you are building your own custom theme from scratch and control the entire ecosystem. My approach is better if you have a theme from another source (i.e. bought or a default Shopify theme), and you want to add a widget or plugin or your own. Both approaches are fine, but how you might set it up are different. I’m working on finding the time to do a tutorial of my approach which is the latter approach. I don’t build themes (right now), I write apps. A common feature for a Shopify app is to add a modal or a component of some kind to a page. If you want to do that without asking consumers to edit their template code, you need to use an approach similar to what I’m talking about.
As far as following the tutorial and things working or not working, that’s not something I can address here. I’m happy to consult and help you build a theme. The alternative is you’ll need to learn the hard way and figure out where things are going wrong. The challenge with these tutorials is they are often stale, and if you aren’t an experienced developer it can be a challenge to close the gaps where things have changed. These project setups with webpack, npm, react, babel, etc… can be very time consuming to setup. The more custom your setup, the more difficult it can be. As a developer, these are the things I usually try to avoid customizing. I like create react app, nwb, and other tools because they abstract away the overhead of configuring all of these things. I don’t want to be a webpack expert, I want to write some apps. Sometimes there’s a really compelling case for deviating from their standard setups, but you’re going to invest a lot of time when that happens or create your own boilerplate setup to save time in the future.