About the only thing you need to do is turn off iMessages on your iPhone. (With iMessages still enabled, if someone is sending you a text message from an iPhone to your new Sunbeam phone, their iPhone will likely try to send it via iMessages, which will not be received on the Sunbeam phone. Turning off iMessages on the iPhone before placing the SIM card into the Sunbeam phone will fix this).
Note: We’ve had one customer report that he was part of a messaging group that was set up when he had an iPhone. When he inserted the SIM card into his new Sunbeam phone, he no longer received messages from those groups. The root cause of the problem ended up being that the groups still had him “registered” as an iPhone user and were trying to transmit messages via iMessage! The solution for him was to be removed from the group and then be added back in again, which fixed the problem.