Alert text under reCaptcha part

First ,thanks for making this useful plugin .

Then, Some of my site visitors are not familiar with this form of security code and before pressing the post comment button , they do not know they should do the reCaptcha . I’m going to put a alert text under reCaptcha part and on top of post comment button and ask visitors to complete the reCaptcha. How could this be done?

please guide me.

Thanks

https://wordpress.org/plugins/advanced-nocaptcha-recaptcha/