Sure! Here are the sentences using the future form of the verb as instructed:

1. Express your intention to have a rest. (going)
I’m going to have a rest.

2. Express the idea that the timetable shows the start of term on 6 September. (starts)
The term starts on 6 September.

3. Predict a world war in five years' time. (there)
There will be a world war in five years' time.

4. Express the idea that you and Judy have arranged a game of tennis for tomorrow. (playing)
We are playing tennis tomorrow.

5. Give your prediction of a probable fall in prices. (probably)
Prices will probably fall.

6. Warn your passenger about the car crashing. (going)
We are going to crash!