Ok, verticle access is the level of interest rates as per RBA, horizontal is the supply of money in the short term money market or the general economy, doesn't really make a difference, but for accuracy its the short term money market.
when the RBA wants to INCREASE rates, it needs to DECREASE the supply of money in the short term money market. Get you ruler, start at equilbrium S1/df now move the ruler to the left, i.e. REDUCING supply, you'll notice the % of the rate increases. that is tighening or contractionary policy. vice versa occurs
easy peasy, you'll need to know this.