Trouble displaying portfolio on home page

So I’ve read through the help page and I’m probably missing something since I’m new to WordPress entirely, but here is what I want:

On my home page, I want my tiled images 3-across just like in the demo. I don’t want any text showing up either below or above it. I can’t figure out how to accomplish this. Here’s what I’ve done:

Created a portfolio of 3 images
Changed my home page theme to “portfolio”

However, it’s giving me an empty box on my home page that I can click on and then go to my portfolio – it’s the featured image box and just appears blank since I don’t have an image selected… but I don’t want this step at all. I want the images directly on the home page. Any suggestions?

Site: 12dogs.net