If you did the kiss cut you should have a sheet of plastic with some pieces of vinyl on it. If it's the perfect layout just leave it like that. If you want to spread out your images you can cut them apart. Then just position them on your fabric PLASTIC SIDE UP this time.
With a hot iron (mine is a little down from cotton so not the max hottest setting) Iron through the plastic. Hold for a few seconds still and then wiggle and them move positions until you've hit all the vinyl. Gently pull on an edge if the vinyl comes up with it iron some more. This step takes the longest especially if you have a large image.
Next I like to flip it over and iron a little from the back. Once you are sure the vinyl is securely attached pull away the plastic. Feel around the vinyl especially at the edges to see if there are any spots that need reinforcement.
I don't always do this step but I find it helpful especially on larger projects where my patience might have me speeding through the last few steps but I place a clean thin piece of fabric down and iron through the fabric for one last bit of attaching.
And there you have it. Now you can customize anything to your hearts content!