Trying to install volta.sh package library

I am trying to install volta.sh package library from which I wish to install Node and npm. I tried:

curl | bash

and got the error:

curl: (6) Could not resolve host: get.volta.sh

I edited the .bashrc and added the code:

export VOLTA_HOME="$HOME/.volta"
export PATH="$VOLTA_HOME/bin:$PATH"

I then closed and reopened the ubuntu terminal. and tried again, getting the same error. Have also tried

sudo apt install nodejs

Which does not work. I am trying to work out what is wrong. Even to update

sudo apt update

results in errors:

Err:1 focal-security InRelease
Temporary failure resolving 'security.ubuntu.com'

I have Ubuntu 20.04 LTS installed. Thank you.

Velvet Digest