How to enable prompt?

For this the most common and most supported technique is to use field-level and/or form-level validation messages.  You could conditionally enable a button confirmation message when some on-form conditions are not met, however this can be tricky to setup and maintain and ends up being a bit of a workaround approach only.

For this the most common and most supported technique is to use field-level and/or form-level validation messages.  You could conditionally enable a button confirmation message when some on-form conditions are not met, however this can be tricky to setup and maintain and ends up being a bit of a workaround approach only.