Load the csv as a normal lookup. Then look at doing an inputlookup of your csv followed by an outlook up to the kvstore lookup. Co sided append=true on the outputlookup if you don't want to wipe out existing data. Talking to your splunk admin would be a good idea on the steps involved if you are new.
If you are more a developer you can modify a copy of this as a method to push csv content to a collection. https://github.com/georgestarcher/Splunk-ESIntel-KVStore/blob/master/splunk-es-threat-intel.py