I’m confused… if you don’t care for the drag and drop features of the program, why did you buy a drag and drop website builder? Bootstrap Studio’s main function is to enable non-coders to create semantic HTML layouts without having to know how to write HTML. If you just want to build sites by writing code, there are free options like Notepad ++, Visual Studio, etc.
In any event, you cannot directly edit the HTML that BSS (Bootstrap Studio) creates. This is the HTML you see in the HTML panel when you drag components into the workspace. You can select individual components and convert them to HTML (right click > convert to HTML) and they will be converted into Custom Code Components.
If you want to add your own HTML or JS to a page, you can drag the Custom Code Component on to the page and double click it. This will allow you to directly type (or copy/paste) your own HTML, CSS or JS code into a window in the Styles panel. Then you just click the Apply button.
If you have created CSS or JavaScript files, you can import them them via the Design panel (lower right), right click on Styles or JavaScript, and you will see options to import your assets.
Or, if you have a complete HTML website page in a folder with assets, you can create a new project, then go to the top menu, choose File > Import and you will see the option to import HTML. When you choose this option, it will present you with more options to parse pages to components, and to scan for assets. This is the fastest and simplest way to bring an entire website created in other applications into Bootstrap Studio. However, if the pages you are importing were not created with the Bootstrap framework, there’s no guarantee the layout will be preserved and functional. It’s not a perfect conversion tool. But it does work.
You can also link an external code editor like Notepad++ or Visual Studio to Bootstrap Studio that will allow you to edit CSS or JS files that you created or imported into BSS in the external editor. When you save the edit in the external editor, it will update the file in BSS.
Hope this answers your question.
I would recommend you fully read the program’s documentation to become familiar with how BSS works, as well as watching the tutorial videos on their YouTube channel.