1. Draw a circle in the middle and write the word "Hoo".

2. Draw several branches outward from the center of the circle, representing the purpose, object and time of the call respectively.

3. Draw some sub-branches on each branch to describe the purpose, object, time and other details.

4. Draw some keywords or phrases on each sub-branch to summarize the content of the branch.

Finally, if necessary, you can add some notes or reminders on the edge or blank of the mind map for reference when making a phone call.