To use First Data SDK you must first initialize it on the Create method of your Application class. To do this you have to call to the initial method of the First Data SDK class with you API KEY and the application context.

override fun onCreate() { 


        FirstDataSDK.init(apiKey, this) 

        //After init you can set the session token whenever you want, but must be done before start any operation. If you only have one session token then we recommend to do it here, like this: