As a recent high school graduate, you may be most familiar with the 5 paragraph essay.
In college, you'll have to move beyond this type of writing, and you will likely learn how to develop and organize ideas in a new way.
Most colleges offer writing centers or something similar to allow their students the opportunity for extra help when it comes to composing essays.
Typically this will include a tutor or someone who will be available to work one-on-one with you.
Plagiarism will really get you in trouble with your professor and the university as well.
Make sure your work is your own and not the work of someone else.
This will help you when it comes to questions in class and will serve as a reminder of what you've read, and it will also help with your comprehension of the material.
The other textbook will likely be a writing handbook.
Brushing up on the basics will really help you hit the ground running.
By doing this, you won't have to try to remember basic grammar rules when you're trying to write an essay.