1. Log as an admin into your Jira instance. 
    In case you have already installed Worklog History plugin, please uninstall it. Otherwise, you will find two sets of information for each issue, which may be misleading.
    Check this page to find out how to uninstall plugin.
  2. Click the admin drop-down and choose Add-ons.
  3. On Find new add-ons screen, locate Worklog HistoryPRO via search. Appropriate plug-in version appears in search results.
  4. Click Get an app to install the plug-in.
  5. You’re all set!