Is the device sending out traps or do you want to poll it from the monitoring server? If it’s the latter, it’s not sufficient to just have the MIBs in place, if Check MK doesn’t support the device already a check needs to be written for it: Writing your own check plug-ins .
If it’s the former (traps) then you can set it up: The Event Console - Processing logs and SNMP traps
Alternatively you can poll certain OIDs you are interested in: Add specific snmp checks to already discovered host - #5 by pn-rallen