i copy the unzip files in this directory:
public_html/app/code/MagePal/Reindex
Your folder location is perfect but after add file folders in your system,
Another time you need to run command for install module. I think you have to issue regardings to server putty refused issue but without run command your module not install.
Run command,
php bin/magento setup:upgrade php bin/magento setup:static-content:deploy
So first you have to resolved your putty issue to working your module. In magento 2 without run command your work will not completed.
if issue solved, Click kudos/Accept as Solutions.