If you're not using the recommended distro (Ubuntu 20.04 for Noetic), you're going to bump into issues such as this one.
As the commenter said, we need a bit more details. Please copy & paste the exact error message you're getting, otherwise we can't really help.
Also, run this command:
$ lsb_release -sc
What do you get? If you don't get focal
, then you need to work around it a bit (because you're not using Ubuntu). Try running this:
$ export LSB_ETC_LSB_RELEASE=/etc/upstream-release/lsb-release
and then executing the command(s) from the tutorial again.
I found this workaround here: https://unix.stackexchange.com/a/543288
"fails looking for lsb-release" -- can you post the error message?