Investing fundamentals give structure to every later choice. We start with goal setting: timelines, numeric targets, and risk comfort. Guides then cover asset allocation, explaining how stocks, bonds, cash, and alternatives move together or apart. Example glide paths adjust mix as horizons shorten or tolerance shifts. Diversification math comes next. Correlation tables reveal why uncorrelated assets smooth returns yet still reach goals. Cost pages warn how fees and taxes erode compounding, with sliders turning fee points into lost dollars. We finish with behaviour: rebalancing cues, loss-aversion checks, and accountability habits that keep plans alive when markets churn.