What is the Week column?

The eighth column on the right. It totals each row of the grid, so you get weekly P&L without adding the days up yourself.

Each row of the calendar is a week, and the narrow column at its right end shows what that week made or lost. A week whose total is exactly zero shows a dash rather than $0, which in practice means a week you did not trade.

The weeks are numbered by their position in the month — Wk 1 through Wk 5 or 6 — not by the ISO week number, so Wk 1 is simply the first row of this grid.