a search on the forum would have found you links already;
start wit the basics;
There are tons of tutorials on Kali available with a simple web search, and if you want to learn how to use the hacking tools, hackthebox or tryhackme are great places to start learning, both have plenty of free content available. Offsec have a great tutorial on using metasploit too!
To learn about networking, the CCNA courses are good, you don’t necessarily need the exams but the content is excellent for learning about networking and routing and switching etc;
This is a free study guide site for ccna so you can learn for free;
What is CCNA (Cisco Certified Network Associate)? - Study CCNA
This article describes what Cisco Certified Network Associate (CCNA) is and how and where you can take the exam.
Est. reading time: 4 minutes
You don’t need programming experience as such, but learning some bash scripting to be able to chain tools together, or even some python is a good start;
Linux Handbook
Bash Scripting Tutorial Series for Beginners [Free]
Get started with Bash Shell script learning with practical examples. Also test your learning with practice exercises.
Learn Bash Scripting | Codecademy
In this course, you will learn how to improve your own programming process by writing bash scripts that save you precious time.
Learn Python - Free Interactive Python Tutorial
learnpython.org is a free interactive Python tutorial for people who want to learn Python, fast.
Learn Python – Free Python Courses for Beginners
Python is a great programming language to learn and you can use it in a variety of areas in software development. You can use Python for web development, data analysis, machine learning, artificial intelligence, and more. In this article, I will…
Then there is practicing your art of course;
Hack The Box: The #1 Cybersecurity Performance Center
HTB is the leading Cybersecurity Performance Center for advanced frontline teams to aspiring security professionals & students. Start driving peak cyber performance.
Become an ethical hacker with this free 15-hour penetration testing course
Learn network penetration testing in this full video course from The Cyber Mentor. This course teaches everything you need to know to get started with ethical hacking and penetration testing. You will learn the practical skills necessary to work in…
How long it takes, depends on how quickly you pick things up really, and the best advice is to get to know people already involved in the field, networking people is perhaps the greatest tool you can have in this field.
After you’ve gotten good with the free stuff I’ve linked too, or feel you are ready for some certs the the best one by far would be the OSCP in terms of proving your creds;
PEN-200: Penetration Testing Certification with Kali Linux | OffSec
PEN-200 (PWK) is our foundational pentesting course where students learn and practice the latest techniques. Earn your penetration testing certification (OSCP & OSCP+).
Est. reading time: 1 minute
Free Ebook: OSCP & PEN-200 Prep | OffSec
Read the free ebook and get prepared for the OSCP exam with expert tips and deep dive through your PEN-200 experience.
Est. reading time: 2 minutes
If your looking for a junior role somewhere first, you could start with some free certs like this sort of thing, just to prove your interest to a prospective employer;
Blue Team Junior Analyst Pathway | Free Blue Team Training
The Blue Team Junior Analyst pathway comprises of six free blue team courses, designed to be a perfect introduction to defensive cybersecurity.
and platforms like hack the box can be used too to showcase your skills.
Happy hacking!