Quickest way from University Station to nearest Walmart?

Just moved in today, and was told the nearest place that sells towels/pillows and other stuff was Walmart. If so, what's the quickest/easiest way to get there?

I don't know how the LRT and Buses work. I have my Arc card, so I just have to swipe it? And how do I know which train/bus to take?

This is my first time in a big city, so sorry for all the probably stupid questions.