Hi Anshu,
I_STEP=1, variable value you will give in the code itself, you cant change the value
I_STEP=3, It is used for validation purpose, you can raise error messages
Let us consider example:
I_Step 1 : let us consider scenario, there is query which is on filter as 'Calday'.. and whenever we execute query then it should ask user date to be entered. AND on date popup there should be calday as today's day populated automatically..
then for this case you have to implement code as "variable = sy-datum" in step 1.
I Step 3 - suppose you want to check authorization for a user to execute query.
you can implement this scenario in I_Step 3.
Regards,
Hitesh