I read the source material multiple times to make sure I understood all the ins and outs. The longer rethinking book I only re-read the chapters that were stumping me, but the shorter texts I probably read 5 times each, specifically chapter 2 of LMM and the MCMC text. I never did any of the problems within the text because I didn’t find them helpful, just focused on knowing every tiny detail in the text. I used TIA as much as I could, but I agree the problems aren’t great. The summary sheets help though