X-axis dimension
The horizontal dimension of the grid — one of the two variables you're crossing. Examples: user segments (individual contributor, manager, executive), channels (mobile, desktop, email, in-person), timeframes (immediate, short-term, long-term). Each column represents one value of this dimension.
Y-axis dimension
The vertical dimension — the second variable. Examples: job-to-be-done categories (capture, organize, share, act), solution types (automation, education, community, product feature), problem areas. Each row represents one value of this dimension.
Grid cells
Each cell is the intersection of one X value and one Y value. Generate at least one idea for each cell. The cell forces you to think about a specific, constrained combination — 'what solution could help an executive share information in a mobile context?' Constraints produce ideas.
Highlighted cells
After filling every cell, highlight the most promising ideas — not necessarily the most obvious ones. Often the cells that were hardest to fill contain the most innovative ideas, because the constraint forced genuine creativity rather than retrieval of existing solutions.