The project you are trying to replicate is really awesome and one needs to have a very good knowledge you HTML, CSS concepts.Complete this project would be a really good opportunity for you.
Now you are thinking how to start and what should i do fist before starting this project, then I would say just dig right in create the html file and start making it right away and since it is a complex project you will be having some difficulties for that you can refer to freecodecamp and similary website.
Although you can check out my portfolio website for some inspiration: https://dev-ashishpal.github.io/
Main difference I found in this video is author has not practiced code earlier but doing trial and error live. In most of the project tutorials authors have already did the project and do hardly any mistakes but Florin has done real world project
@vikramvi I checked out your initial link and that website is quite beautiful. If you are still interested in learning from it, it is built in a framework called Bootstrap (I am learning Bootstrap right now). Here are the docs, which will give you an idea:
There are videos to teach bootstrap, too. I made this site over the last day or two using Bootstrap: