Yes, that's right! You can follow this tutorial here to add a back in stock notification form to your site. When a customer uses the form to submit their email address, you will be sent information about the product that they are interested in. Currently, with this method, you would manually need to reply to the emails that have been sent to you in regards to the out of stock product.
If you're not a big coder, and you'd like a free way to reply to customers who want to be notified when products are back in stock, the below method can be used as a workaround:
1. Set up a filter for your inbox where the 'notify me' emails are being sent. Here are some instructions for Gmail on filtering messages (Each inbox varies slightly, use keywords that relate to the product name.)
2. Use the Email Address Extractor (If you're using Gmail) to give you a list of emails on a Google Sheet.
3. Upload the email list to service such as MailChimp.
4. Send out a mass email notifying all the customers who submitted a form about that particular product.
Alternatively, you can use an app such as Back in Stock, Back in Stock Alerts, Stockify and In-Stock Alerts. These apps let customers signup for in-stock notifications and sends an email notifying them when you restock.
If you'd like to create an app yourself, a challenge to be aware of is, that you need to create a service that will gather the email addresses, and fire a response on your behalf when there's a trigger. The apps often integrate with mail services such as MailChimp to help them with this process. If you wanted to go one step further like Back in Stock, you can even connect this trigger directly to the stock levels so the notification process is automated. As a new dev this is quite the undertaking, however, it can be done! Check out the Shopify API Help Centre here if you haven't already. This is also a neat article on how to build an app in one week.
Best of luck!