Usually when I'm stuck on something I just put faith in the directions and keep going. I did ask our tech editor if she had any advice for you, and in case others get stuck, here's what she said:

The clusters in the Sparkly Snowflakes are a lot like working a dc2tog EXCEPT that you work both of the dc's into the same st or space (rather than one dc in one stitch and one dc in the next). So, to work a cluster in a stitch follow these detailed steps:

1) yarn over and insert hook in the stitch,
2) yarn over and draw up a loop (you should now have 3 loops on the hook),
3) yarn over and draw through 2 loops on the hook (you should now have 2 loops on the hook) - Note: you won't complete this dc right now.
4) yarn over and insert hook in the SAME stitch,
5) yarn over and draw up a loop (you should now have 4 loops on the hook),
6) yarn over and draw through 2 loops on the hook (you should now have 3 loops on the hook) - Note: now you have worked 2 "incomplete" dc's in the same st.
7) yarn over and draw through all 3 loops on the hook - Note: this completes the cluster

We hope this helps.

Look at your local yarn shop or bookstore. Or you can call 800-865-7240, or search online for a vendor.