Canvas is one of my favorite things to work with.
It's heavy and well . . . .it's a blank canvas for doing all sorts of things.
Go to your local art supply store and have them cut you a few yards of unpainted cotton canvas. At Blicks they have it by the yard on bolts. So it's very easy to purchase and really very inexpensive.
Here is a quick table runner I made today.
Now layout the canvas on a flat surface and arrange your buttons in a heart shape whereever you want them. I put three at one end and three at the other. Make sure the hearts are off set from each other so it doesn't look boring.
Now grab your glue gun and lift up one button at a time, dab a little glue on the reverse side of the button and place right back into the heart shape. The canvas is very forgiving if you glue a button in the wrong place just rip it off and rearrange. No harm done.
Have a good end of January.