To use the bagua chart, line up the bottom with your front door. The entrance of your house or apartment will be in the Career, Helpful People/Travel, or Knowledge/Self-Development areas. The right corner is your Love and Relationships area, the far left your Wealth/Prosperity area, etc.
You can also use the bagua for a specific room to add Feng Shui adjustments. Just line up the bagua with the door as you look into the room. Then you can adjust and energize the areas of interest.