While your account is still in onboarding mode, any admin who is not a super admin or a Sprwt onboarding user is redirected to /admin/onboarding whenever they open the plain /admin dashboard, until either every onboarding task is complete or someone clicks Continue to Next Step on the Onboarding page. That button (after an Are you sure? browser confirmation) sets a flag that stops the redirect for everyone on the account from then on, even if some tasks are still incomplete - use it once your team is ready to work from the normal dashboard instead of the setup checklist. It only appears while onboarding is still active; once it has been clicked (or onboarding is fully complete) it disappears.