You need to create a dsm.opt for each instances. Then within the dsm.sys file, create a stenza for each instances...
from there , you need to start, for each instances a dsmc sched that points to each dsm.opt created.
For example:
dsm_os.opt contains
SERVERName NodenameA
and dsm_data.opt contains
SERVERName NodenameB
Your dsm.sys would look like this:
SERVERName NodenameA
COMMMethod TCPIP
TCPServeraddress x.x.x.x
include/exclude etc...
SERVERName NodenameB
COMMMethod TCPIP
TCPServeraddress x.x.x.x
include/exclude etc...
And then, as mentionned you start your processes...
Start your dsmcad process and then start one dsmc sched -optfile=/pathtodsm.optfile/dsm_os.opt and dsmc sched -optfile=/pathtodsm.optfile/dsm_data.opt