Go get CompTIA Network+ certified. There’s plenty of material (prof Messer in particular). After that, play around with simulated network with GNS3 or similar software. Learn to SSH tunnel through multiple hosts. Play with socat and other low level networking tools. Implement some basic apps with your language of choice. Learn wire shark doing wire shark CTFs. Finally, reimplement a networking protocol from a spec.
Congrats you know networking now.