Decision Trees, Random Forests, and XGBoost

Decision Trees

You've got plenty of options learning this stuff. This fellow at Google was exceptionally clear, though, especially when walking us through gini impurity.

Random Forests

I was always happy to see a video by Ritvik, the author of the second video in this section. He's got a great, mellow way of explaining things, and the white board helps keep it simple.

XGBoost

At least ~2021-2022, most ML professionals on social media would say XGBoost was the gold standard for tabular ML algorithms. Ritvik below calls it "data science's silver bullet."

You'd probably also want to find a code-along notebook somewhere on XGBoost. If I were to revisit the subject I would start on Kaggle probably, or just mess around with the library (opens in a new tab) on Colab.