TI-84 plus calculator help? Can't graph correctly?

I got this calculator for my math class as i take high school classes now. Now before, in a math program i'm in, i made two graph lines at one time. So tried to do it again but it is not working. Can someone tell me how to graph two lines at once on my calculator. I read before to change the slanted line at the y= editor but for my calculator,slanted lines don't show up,but rather triangles that look play buttons on a dvd player. Can someone help me?