You don't need any paid LinkedIn subscription to add candidates to the HeroHunt.ai extension. Any profile on Linkedin can be added to your Engage flow by simply clicking "Add to Engage", even from the free LinkedIn search page.

​You can install the HeroHunt Browser Extension here:
​https://chrome.google.com/webstore/detail/herohuntai/nmflpfdfaamlajlhhmlpdffplghijdfl
​
The main function as of now is to add potential candidates from LinkedIn to Engage flows, so after installing the chrome extension you'll see this button added to LinkedIn profiles:

​These are some of the things you can do with the extension:
- Add a list of candidates in one go to Engage (from LinkedIn search page)
- Manage engage flows from the Chrome extension
- Perform additional actions from the extension like finding contact details manually