A horizontal bar chart displays population data for ten countries, with custom tick formatting abbreviating numbers by converting "G" to "B" for billions. The example uses d3.csv to load data, d3.scaleBand and d3.scaleLinear for scales, and d3.axisBottom with d3.axisLeft for axes. Custom styling removes default domain lines and adds a centered axis label and title, while tick lines extend across the chart using d3.axisBottom’s tickSize.