Domain

How to purcahse domain ?
and then how to make more and more traffic?

You can buy domain on namecheap for example or namesilo they have .com for like 1$ (hope promo is still running)

Traffic can be generated by doing SEO or paid ads

Buying a domain's easy-peasy. Namecheap, GoDaddy, Dynadot – all solid registrars. Just search your desired name, check availability, and checkout.
Now, driving traffic? That's the grind. Start with on-page SEO, make sure it's on point. Create killer content targeting long-tail KWs initially.