Hi,
I assume you are allowing guests to checkout without creating an account hence requesting for tracking by IP address?
Here are the steps you will need to follow in order to set this up, In the plugin’s settings
General > Mode > Product QuantititesÂ
General > Date range > Lifetime (Or as per your requirement)
General > Order statuses > Select the relevant order statuses
General > Guests > Identify Guests by IP
General > Block guests from buying products > Block Method > According to limit options
Limits > Per product > Enable
Then edit the sample product and you will find a new field for maximum products per user. Set this as 1
You can configure if you want to display the limit exceeded message on the product page or cart page from the Frontend tab.