Docker Error while installing IDHUB

I’m trying to install IDHUB with the instructions at - https://docs.sath.com/idhub/IDHub-Installation-Steps.189991778.html. I am on Step 5. The Error is about docker. Any idea how to resolve this?

ERROR: Couldn’t connect to Docker daemon at http+docker://localhost - is it running?

You need to run the installer with sudo

sudo ./install.sh