Follow the guide below.
To start multiple clusters on the same host, create separate directories for each cluster and extract the geneos-openaccess-node-X.zip there.
Open oacluster.sh and find the OAC_NODE_PORT_BASE and OAC_JMX_PORT_BASE variables as shown in the screenshot:
The default values are 2550 and 9990, if you start a node using these defaults it runs on the base port + 1 => 2551 and JMX port 9991.
So if you want to start a second cluster, go to its directory, open oacluster.sh and change the base port variables to e.g. 3550 and 10990.
Make sure you edit your application.conf and change the port there as well, so if your base port is 3550, the port in application.conf should be 3551.