Installation
At first, the Switcher application should be added to your Jira. Read how to find, add and manage the Server apps (Atlassian documentation).
Configuration
After installation click the Configure button (or find the app in the list of Teamlead apps in Jira Administration → Manage Apps → Teamlead → Switcher Settings) and specify:

Audit Log
The Audit Log tab contains the information of Switcher functionality used by Jira users.
