Often the easiest way to find the values you're looking for is to use an SNMP Browser. Most SNMP browsers can scan a device, retrieve all of the values it supports, then present them to you in a list or in a tree-like display so you can navigate to the area you are interested in. There are many different SNMP browsers available and they range in price from free to several hundreds of dollars depending on the features and functionality included.
See our SNMP Browsers resource page for a list of SNMP browsers to choose from.
See our list of network monitoring solutions that support SNMP for a range of selections that also range from the free to the very expensive.