abap - First time creating a user exit/enhancement in SAP -

i've watched quite few videos on youtube , have basic understanding of how find user-exits (enhancements?) , implement them. when try replicate i've seen doesn't appear working.

i'm looking create user-exit execute when production order has been confirmed (closed/finished) via co11n. suggested put in line of code "break username." verify code firing. nothing breaks. i've tried putting in message code found on internet

message s208(00) 'test'. 

no message shown. i've activated include , project. i've tried different exits/includes , no matter do, nothing seems break or show message.

is there simple i'm missing? i've tried confpi05 , confpm05.

i checked documentation:

confpi05 update own data after saving confirmation

in another documentation found warning:

in customer enhancement strictly forbidden send error messages or other messages because otherwise there danger data inconsistent. sap cannot held responsible this!!

this sounds changes in update task. default breakpoints in update task not enabled.

should code processed after pushed save?

if yes, can try:

• set anywhere breakpoint. or try /h during data insertion.
• in debug screen activate update debugging:
• continue process f8.
• hopefully stop @ break-point.