Searching substring within database


I have a database of users. I want to build a user search page that allows you to search for all users by their first or last name.

My repeating group’s datasource is: Search for Users with constraint by first name (as shown below). I have also checked the Ignore Empty Constraints box.

Let’s say I have a list of users: Anna, Bobby, Catherine

When I search “An” it comes up with no results. It only comes up with 1 result when I search “Anna”

Is there any way I can fix this?

NOTE: I ideally want the fix without using the Search&Autocorrect plugin