Never do anything directly on a live store. First setup and test on a development domain (i.e. “dev.url.com”).
Temporarily disable Magento cache
To avoid any possible issues with the installation we recommend disabling Magento cache before proceeding with the installation and re-enabling it once the install is complete.
Upload Acx Stock-notification
Using your favorite FTP client, upload all files and folders to the root folder of your Magento installation
For how to enable magento 2 module follow this link.
In 'General Settings’ Admin can define the notification method as Automatic or Manual. In Automatic option, the notification emails will be sent automatically to the user when the product gets back in stock. In Manual, the admin has to manually notify the users. In Admin Email id field, the Admin has to set an email id from which all the notification emails will be sent to the users. In Admin Name, the admin has to enter his name.
If a guest user wants to get notify about a product getting back in stock, then he/she can simply enter their email id and click on ‘Notify Me‘ and then whenever that product gets back in stock and available for purchasing, the guest user will receive a mail on the mail id that he/she has provided for receiving notification.
Whenever registered users visit an out of stock product page, they will see that their email id is already been filled in the email id field, they can also change the email id if they want and after that, they can click on ‘Notify Me’ to receive notification when the product gets back in stock.
Thank you for reading this user manual! We'd be glad to help you if you have any question relating to this extension.