Question about custom collars

[GhostCollective Resident]

So i finally got PS and have tried my hand at making some collars. Now the next step for me is to figure out how to make it transparent along the edges, I was given a template that said whatever color is in the center would also make the edges that color. However what I'm having trouble figuring out is how to position my design so it will come up transparent like if i wanted to do any lace type designs. Any ideas please, not an expert on PS, really just starting out with it. thank you in advance.