There are 3 ways that I know of to move to Vanuatu.
1. Buy or start a business. This gives you the right to apply for residency supported by a VIPA (Vanuatu Investment Promotion Authority) approval and work within the business.
2. Buy a house or other property. This gives you the right to apply for residency only and may also require evidence of income to support yourself.
3. Self funded retiree. You must provide evidence of income to support your application for residency (unsure what the minimum is).
To become a citizen, you must be a resident for a minimum of 10 years before submitting an application. Vanuatu has just approved dual citizenship.
Most of the real estate sites have lots of information about moving to Vanuatu. Just Google "real estate vanuatu" and take your pick.