Adding Magnifying glass to Search Button

I'm using the WP Search Block. I've read through all of the support topics and I think maybe those answers apply to a Generate Press Search Block?? I don't know. Am I using the wrong search block? I can't find a Generate Press search block.

All I want is a magnifying glass in the search button. It works fantastic on the search bar in the menu (I believe that search function is from GP), but I'm at a loss as to how to get it to work on the page using a WP Search Block.

Please tell me what I'm doing wrong here. Thanks!