Start up Shifter Headless WordPress
1. Login to Shifter Headless dashboard
https://go.getshifter.io/admin/headless/
2. Click "Headless"

3. Click your Headless site icon

4. Click [Start] button

5. Booting WordPress

6. Running

7. You can access WordPress dashboard with initial credentials if you haven't changed them.
If you have changed them, use updated.

That's all.