Watson ibm key credentials

I try to run watson ibm

I use this:

library(WatsonR)
watson.alchemy.test()

but I receive this error:

[1] "Short Test of Alchemy - Hitting Endpoint; Checking Credentials OK and Transactions Consumed " Error in fromJSON(, creds) : either json_str or file must be supplied to fromJSON

Is there any idea how can I insert the keys credentials?