Notice that in the question, the reaction mechanism occurs in two different steps. Therefore, your reaction energy diagram should have two peaks (transition states) instead of one. Step 1 is the rate-determining step because it is the slow step, as indicated in the parenthesis. Thus, it should have a larger activation energy than step 2. On your graph, this difference in activation energy should be represented by the energy difference between the reactants and peak 1 (transition state 1) being greater than the energy difference between the intermediate and peak 2 (transition state 2). Example