how to pick

RouterOS Scripting
1

pls help

2

Possible what? Search sms for text?
Can you be more specific?

Maybe something like this

/tool sms {
  :foreach msg in=[inbox find] do={
    :if ([inbox get $msg message]~"regexp") do={
      :local senderNumber [inbox get $msg phone]
      ....
    }
    inbox remove $msg
  }
}