Briefing template for trainees ideas

**Background**
We have a current [briefing template](https://docs.google.com/document/d/1u1uLQMU4cwRQTrik_C17k0vpeSAhzGPG5IskTeF5BCc/edit?usp=sharing) that is used for the [CYF Briefings](https://drive.google.com/drive/u/0/folders/1UocnK_dRUkMCuwI6aytZ0Z9a12322EOx). The WM5 and NW6 people have great ideas of their own projects. Can they use the same template to describe what they'll be doing?

This is a quick-win, not the perfect solution

**Acceptance criteria**
- Read the current [briefing template](https://docs.google.com/document/d/1u1uLQMU4cwRQTrik_C17k0vpeSAhzGPG5IskTeF5BCc/edit?usp=sharing)
- Ensure we are happy with it (only must have changes to be proposed)