Establishing transport route between source and target tenant is the first step towards, this blog describes step by step how to pair 2 tenants

Pre-requisites – please assign the needed roles to the user by following the SAP help documentation here
Instance Pair Wizard
Step 1:
Goto Configuration Transport Center > Transport Routes > Click on Add New Pair

After filling the details for the target tenant and environment, you need to press generate token
Step 2:
Now, Login to target tenant > Goto Configuration Transport Center > Transport Routes and copy the generated token by clicking on copy token
Step 3:
Paste the token in the source tenant “instance pairing wizard” screen and click on validate

Step 4:
This completes the instance pairing configuration, which will be confirmed on the screen – you should be able to see the same in the transport route details.

Conclusion:
- This is done via “Transport Routes“ section in the configuration transport center tool UI
- Pairing instance is guided by “Instance Pair Wizard“ through 4 steps – no restriction on the environments and data center, the list is up to date
- Deleting an instance pair always happens in the source system
- Please check this Implementation Design Principle for scenario specific example and benefits of Configuration Transport Center - SAP SuccessFactors HCM: Configuration Lifecycle Management