Error Message revision

I have a very simple product offering and would also like a single sentence error message. This would be a fantastic product if there was instruction on how to edit the error message. For us non-developers, we can handle switching a line of code here and there. I don’t know which files to alter within the plugin to change the message to a single line. It would be a 5 star product otherwise.

https://www.ads-software.com/plugins/min-and-max-purchase-for-woocommerce/