From the manual it states:
                                                                                                                                                     

                                               
•                                                        
  Paring Batteries: Powered by two batteries (with battery cells connected in parallel), the Inspire
                                                         
  2 requires that the two batteries should have similar properties, e.g. internal resistance. It is recommended to pair the batteries from the very beginning inside the DJI GO 4 app. DJI GO 4 app will also prompt when the batteries that are not paired are in use. The Intelligent Flight Battery Charging Hub will charge the paired batteries simultaneously. The pair sticks is available for paired batteries.
  
  
  
  
  Any idea how you actually do this?
  
  
  Regards,
  Tom
  
  
  
  
                                         

                               
                       
               

With the two battery I2 setup, DJI introduced pairing into the GO4 App with the intention of having the GO4 app match battery serial numbers defined within a pair, as well as looking for similar charge and discharge cycles. As with any newly introduced software, we may come upon integrations in the total system that may not be recognizing the pairing. So until the software is bullet-proof, it is still best to label your batteries so that YOU recognize a pair. Charge them together, have them set for automatic discharge similarly, update them together, and fly them together.... Just a recommendation and always fly safely.

use the little stickers inside the new battery pack

I also wanted to pair my new batteries today,... wasn´t able to find info (only the info that users should pair them within the Go 4 app )

Tap the battery icon in the GO 4 app you will see at the top right either it will say paired or pair now.