Don't take it the wrong way but if you don't know that, it's better to leave this to someone qualified. Engage your local Splunk partner or create a case with Splunk Support if you have problems with your environment.
But as you seem to already have some issues with your data, don't blindly run some commands in hope that something will help because you might damage your instance irreversibly.
BTW, the docs are pretty clear on this and since you have to take the indexer off-line I think it's self-explanatory enough.
