If you are a beginner and to start Ethical Hacking, learn the basics of networking, programming, databases, and operating systems (Linux and Windows). The only pre-requisites are the capabilities to dive into a lot of strings of data and codes. You also must have a perfect machine, aka laptop, and VPN.
I would recommend to take up this Ethical Hacking online course considering time problem, assistance from professionals, and to speed up the learning process.
If you are looking for an online course to learn Ethical Hacking, check out this Ethical Hacking Training by Intellipaat.
Also, you can watch this video for more information: