I have a form with tthree field "First Name" , "Last Name" and "Date". I want to generate a case number using these fields. So, I created a Variable Named "CaseNumber" and the value equals -

"CASE"+"-"+substring(toUpper([Form].[First Name]),0,2)+"-"+substring(toUpper([Form].[Last Name]),0,2)+"-"+formatDate([Form].[Date],"DDMMYYYY")

When I try getting the first two letters of First Name or Last Name it Provides the Full text of the respective fields. What could have gone wrong ?

In this I have substring First Name with 1,2 and Last Name with 0,2. I was Expecting Output as

"CASE-ON-ST-04092019"