free5Gmano installation questions

The installation guide for free5GMano is a little confusing. Should we post questions about free5gmano here as well?
This is the error we got stucked during installation:
kubectl apply -f multus-daemonset-pre-1.16.yml
unable to recognize “multus-daemonset-pre-1.16.yml”: Get http://localhost:8080/api?timeout=32s: dial tcp 127.0.0.1:8080: connect: connection refused

Hi ywang06,

Have you completed the installation? I just start to try it but it failed at verify first step.
ubuntu@ubuntu-KVM:~$ sudo apt-get install -y kubelet=1.15.3-00 kubeadm=1.15.3-00 kubectl=1.15.3-00 --allow-downgrades
Reading package lists… Done
Building dependency tree
Reading state information… Done

No apt package “kubeadm”, but there is a snap with that name.
Try “snap install kubeadm”

No apt package “kubectl”, but there is a snap with that name.
Try “snap install kubectl”

No apt package “kubelet”, but there is a snap with that name.
Try “snap install kubelet”

E: Unable to locate package kubelet
E: Unable to locate package kubeadm
E: Unable to locate package kubectl
Then, i manual install “kubelet,kubeadm,kubectl” using below commands:
ubuntu@ubuntu-KVM:~ sudo snap install kubeadm --classic kubeadm 1.18.4 from Canonical✓ installed ubuntu@ubuntu-KVM:~ sudo snap install kubectl --classic
kubectl 1.18.4 from Canonical✓ installed
ubuntu@ubuntu-KVM:~ sudo snap install kubectl --classic snap "kubectl" is already installed, see 'snap help refresh' ubuntu@ubuntu-KVM:~ sudo snap install kubelet --classic
kubelet 1.18.4 from Canonical✓ installed

But when i try to show version it generated below error:
ubuntu@ubuntu-KVM:~$ kubectl version
Client Version: version.Info{Major:“1”, Minor:“18”, GitVersion:“v1.18.4”, GitCommit:“c96aede7b5205121079932896c4ad89bb93260af”, GitTreeState:“clean”, BuildDate:“2020-06-18T17:02:08Z”, GoVersion:“go1.13.12”, Compiler:“gc”, Platform:“linux/amd64”}
The connection to the server localhost:8080 was refused - did you specify the right host or port?

I also try to disable swap, but it still displays that error. Please provide some ideas on this.

Thanks