Hi Gokhan,
SetOtherMetaHeaders function basically take key/value parameter along with method request to find the meta information of the user. Above functionality that fetching the additional data of the user from storage service along with User object is documented here, however, we are also in the process of updating our tutorial and docs with every single use case which user might have. In the meanwhile, please shoot any question which you have in terms of implementing the App42 SDK or you have some technical concerns or you need help to understand the best practices of data insertion in App42 Database.
Please let me know, I will be Happy to address your concern.
Regards,
Himanshu Sharma
App42 Team