I am referring to the following link Installation Link for installing Kubernetes on Ubuntu 18.04. I am getting the following errors on typing the command :

sudo kubeadm join 192.168.0.114:6443 --token qgce4f.tgzda1zemqnro1em --discovery-token-ca-cert-hash sha256:6ebc15a5a9818481f8a98af01a7a367ba93b2180babb954940edd8178548773a ignore-preflight-errors=All

W0303 18:33:39.565868    7098 join.go:185] [join] WARNING: More than one API server endpoint supplied on command line [192.168.0.114:6443 ignore-preflight-errors=All]. Using the first one.
[preflight] Running pre-flight checks
    [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 18.09.3. Latest validated version: 18.06
[preflight] Some fatal errors occurred:
[ERROR DirAvailable--etc-kubernetes-manifests]: /etc/kubernetes/manifests is not empty
    [ERROR FileAvailable--etc-kubernetes-kubelet.conf]: /etc/kubernetes/kubelet.conf already exists
    [ERROR Port-10250]: Port 10250 is in use
    [ERROR FileAvailable--etc-kubernetes-pki-ca.crt]: /etc/kubernetes/pki/ca.crt already exists
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`

Can someone please tell me how to fix this? Thanks !