How did protective tariffs such as hawley-smoot affect the cycle of depression shown in the diagram

Without you providing us with the diagram, I can still offer you some thought about the effect of the Smoot-Hawley Act and protective tariffs.  Sponsored by Senator Reed Smoot and Congressman Willis Hawley, the intent of their tariff act was to protect American jobs during the economic crisis of the Depression. However, when the US imposed protective tariffs, other nations retaliated with tariffs of their own.  Thus American exports and imports were cut in half and the Depression grew worse, not better.

We should note this too:  While economists agree that Smoot-Hawley worsened the Depression, how large of a factor it was is a matter that economists debate.  Some say the tariffs played a minor role compared to other aggravating factors of the Depression.  However, the Foundation for Economic Education asserts that the economists who want to minimize the role of the Tariff Act are wrong to do so.  Underestimating the negative impact of protective tariffs can be very dangerous economically -- then and now.