Snmp mibs querry

i’am collecting metrics using snmp from my firewall Fortigate 100 D UTM and i got some variables on my querry that i couldn’t understand them !
what shall i do to understand them one by one !
PS: they are differents at fortigate MIB : https://help.fortinet.com/fgt/handbook/40mr3/Handbook_Online/wwhelp/wwhimpl/common/html/wwhelp.htm?context=Handbook_Online&file=monitoring.24.25.html