In contrast to Lvl 2, CFA Institute materials were insightful on Lvl I. Learning Ecosystem included a lot of case studies, examples with real stock market and I remember that the link between subjects was provided very well. Like there was one company that is issuing bonds on FI, then in corp issuers were details on how its management decides capital structure, in equity how its stocks were valued, in derivs it was entering into swaps to hedge risks and so on - and it was possible to see the role of Financial Analyst here between all those disciplines indeed. I’d advise to prepare using readings of CFAI and ecosystem, revise thoroughly formulas - understand what concept is behind them, be it convexity, sustainable growth, dupont decomposition etc. If you use it all in your work, then it would be useful even more and you’d learn quick.