grain can matter but it can be done if it's not important like when you are doing blocks or strips that have to match up. I once cut a block and it wasn't on grain and it took me the longest time to figure out why it wasn't square; one side shorter than the other. You can applique it anyway you want. I like to do backbasting or fusible but it's up to you. Try it different ways and see what works best for you. Congratulations on getting those dies; I got the gingham cat and dog and now want sam and sue