Hi Nishant,
which plugin are you trying to install? Auto enrolment (https://moodle.org/plugins/view/enrol_auto) or Auto enrol (https://moodle.org/plugins/view.php?plugin=enrol_autoenrol).
The screenshot posted by Stephen is about autoenrol, but the link you provided is about auto enrolment
The right folder for Auto enrol is enrol/autoenrol.
Bye
Sara