How should I set up this Formula URL button

Let try this

var text APPTOKEN = "b6w3x2vddzcyk3c8upwsnbu5vqbw";

// Define the Approval URL to add a new record to the DECISION STATUS CHANGES table
var text APPROVED =
URLRoot() & "db/" & [_DBID_DECISION_STATUS_CHANGES] &
"?a=API_AddRecord" &
"&_fid_99=" & URLEncode ([Record ID#]) & // set 99 to be the field for related parent.
"&apptoken="& $APPTOKEN &
"&_fid_25=" & "Approved";

var text LandingPage = URLRoot() & "db/" & AppID() &
"?a=dbpage&pageID=2";

$Approved
& "&rdr=" & URLEncode($LandingPage)