How do I determine the Required Minimum Distribution for a simple Indiana PERF pension?

Generally, the amount that you receive from a pension IS the RMD if you are at or beyond the normal retirement age for the pension plan. So just enter the amount of the distribution as the RMD.

Say all of it is the RMD.   If you need to take the RMD it will ask you if it is the RMD.  Say yes.  Anything your pension pays you is considered to be the  RMD.  Traditional pensions automatically fulfill the rules of an RMD. So for the RMD question put in the same amount as box 1.

If you reach age 72 after December 31, 2022, you must begin receiving required minimum distributions by April 1 of the year following the year you reach the age 73.