For that first step, please email me at resnik@umd.edu with your permission request, and include (a) what year you are in, (b) why you'd like to take the class, and (c) any previous coursework (with final course grade and who the instructor was) and/or research experience that could be viewed as helping you prepare for whatever the course is about.
Please note that undergrads who take my grad classes are treated entirely equivalently to grad students in the class, in terms of workload and expectations. I can't promise that I will grant you permission to take the class, but you're welcome to ask.