So basically, the internet runs on TCP/IP, which is provided by an ISP.
Reticulum is a new protocal in the same spot - it puts packets out.
However, while your TCP/IP address is usually tied to your location, and unencrypted, Reticulum is tied only to a cryptographic address. Which means that it can go anywhere, via any path - and is encrypted while it does so. Only you can unpack the packet and see what's in it, so your ISP can't spy on you, and it's hard to block access.
And this also means it's easier to work on different physical media - so Reticulum can work over LoRA (low wattage) radios, that are similar to walkie talkies in power and don't require a license. If you've got these running, there's no way an ISP or phone company can stop people from talking to each other.