You're thinking VisualBasic which has more bells and whistles like "PRIVATE SUB CMDHELLO", but none of that existed in the original BASIC of which SmileBasic is based on. Just the good o' fashioned PRINT "Hello world" (or ?"Hello world" like Keiren said). Type these in EDIT mode though, not the DIRECT mode in this screenshot.
1そうだね 未プレイ