I am planning a trip on the summer, and I need help learning how to crate, Tinkerbell has never been crated before, I hope she doesn't freak out

.I bought this crate today. I hope you all can guide me on this one. Oh yeah I almost forgot, she is used to being free all day, How can I make this easy? She is almost 4 months old, does that makes it harder or is it still time?