Curiosity about phone palm SMS

I'm using 1,000 phone farms for YouTube. I want to start an SMS business, but my device currently uses Wi-Fi and a VPN without a SIM card. How do I configure multiple SIM cards? My location is Korea.

It is extremely hard to run an SMS campaign off phone farms because your phones are tied to a single location, especially if you're running 1000 phones, they would get banned very fast unless the vpn you use is a residential proxy and you regularly change it. A better idea would be a sim reader/modem because they are much more secure they are cheaper long term because you swap it out when sim die