Fill In PNG Image Created In Photoshop With Swatch

Hey there guys, I'm having trouble filling in my PNG image with a swatch. I've viewed tutorial after tutorial and seemed to be a straightforward process, but nothing I have tried is successful. Anyone have any idea what I need to do or what I'm missing? I need the logo to be the swatch shown, keeping the transparent background. Bonus: First things first, but I'd eventually need/like to make the logo overall thicker, if anyone could help on that would be soooo greatly appreciated, I've also looked everywhere and couldn't find anything. Thank you in advance!