Port and clustered

hello every one
i need to deploy clustering and replication to my data i had read this post


when i run this
couchbase-cli cluster-init -c–cluster-username aya --cluster-password 123123 --cluster-port 9091 --services data --cluster-ramsize 2048 --cluster-name second
it told me it was exist then i run
couchbase-cli cluster-edit -c–cluster-username aya --cluster-password 123123 --cluster-port 9091 --services data --cluster-ramsize 2048 --cluster-name second

to create another port the
the result is i couldnt open the intial port which is 8091 and the cluster name is first
as i understand i should creatre different port to create clusters
as they mention
( To set up a cluster, you need to install Couchbase Server on multiple nodes. In this section you can find instructions on how to do so, please follow these instructions to deploy 3 nodes. Later on, we will refer to those as node-1 , node-2 and node-3 .)
how i can set up nodes

could any one help me as new with couchbase especially clustered one