In the Health App:
1. click health data section on the bottom.
2. Pick whatever vital section you want to appear as a dashboard (for example > sleep > sleep analyist)
3. Click "show on dashboard" (this adds the entry to the dashboard)
4. You have to manually go into whatever you added and enter data yourself.
The only dashboard that is automatically populated is Steps, Walking+ running distance, Flight climbed. Everything else has to be keyed in by hand. e.g. how would your phone know how much you ate to track your calories for example?