How to install rsetup on ubuntu with rock 5b

I want to set overlay by rsetup, but it showed ‘command not found’ on ubuntu, how could i install rsetup on ubuntu?

If You are using ubuntu from radxa then it should be already there,
I’m not sure if its reasonable to use this on different image than the one from radxa, there is radxa apt (probably outdated) and radxa rsetup github repo (You should be able to install deps and build it).

Rsetup only available on radxa OS(Debian), not on Ubuntu OS.
It should be necessary to manually add overlay, but I need some help for it.