WhatsApp marketing strategy

If I want to start with whatsapp marketing, where should I start.Are this steps correct?1. Buy chaels like this ones here (there are plenty of this sellers)2. Find numbers, which software can I use to see if they have whatsapp?3. Find a whatsapp marketing software that can send to lot of whatsapp users?Are there something else I need to do? The problem I see is that this guy only have chaels with Asian whatsapp number. And I need US/EU numbers. Do you know any seller with US/EU number?Are here someone that can help me to scrape phone numbers?