SM 9.41 - Date-Timestamp with Operator after typing in notes

Good Day,

I'm in need of some scripting guru's who can help me with this next question.

I need a date-timestamp plus the operators name after they make a change to an incidient.
How does one set something up like this and where do they go to do this? The book material is a bit lacking and I believe that you need some serious Service Manager smarts to accomplish this and I know this is out of my league. 

Here is what I am looking for.
1. Enter in the information needed into the 'Comments' field.
2. Hit the save button.

testmessage.png

3. The 'Comments' field was added to the 'Problem Description / Information' field with the additional information in red. This is to simplify the note taking process for the operators who work on many of these incidents.

testmessage2.png

 

Any information of help on this is greatly appreciated. If you could help point me in the right direction please be concise :D and very literal. Someone help me with this MOMENTUM!!