Your account manager can guide you through the process and can advise you on what licensing you will need. To cluster any Qlik product that requires a license the license has to have that information in it.
To Cluster QVSs
NUMBER_OF_CLUSTER_NODES;4;; with 4 being the number of QVSs.
For the distribution service (Publisher)
NUMBER_OF_XS;2;; with 2 being the number of distribution services.
The above numbers can be more depending on what you purchase.
Is it possible to run two publishers in a Non-Clustered architecture, but managed through the same QMC?
Have another license but would need to first add the Distribution services on the Setup tab. However, when trying to add am getting an error saying - Can not add more distribution services, you only have 1 in your license.