How do I link two Jira instances?

You can't link the two Jira instances directly. You need a third-party app for this purpose. The recommended apps are Exalate and Backbone. To connect them using Exalate, follow these steps:

1. Install Exalate on both instances.
2. In one of your Jira Instances, open the App Menu. Now click Exalate and tap Connections.
3. Enter the URL of another instance and click Initiate.
4. You will find an invitation code. Save it for later.
5. On the other instance, click 'Accept the invitation' and enter the code.
6. You can further configure the options to share data.