How to understand it
Whole-sign houses assign each complete sign to a house, beginning with the sign rising at the eastern horizon. Other systems draw boundaries differently; comparing charts requires knowing which system was used.
An example
Think of planets as the topics in a sentence, signs as style, and houses as the setting. A planet in the sixth house might invite questions about daily routines without predicting a specific job or illness.
Use it carefully
If your birth time is unknown, keep houses and the ascendant unset. A guessed time can create a convincing but unsupported story.
Try a reflection
What changes when you read a placement without assuming its house?