There is a comment/dialog box at the bottom of main Vassal window. It might be what you are calling the chat bar. Whatever is entered there while recording the log file will be displayed as the logfile is played back.
The logfile should begin before the first initiative roll. I usually open up the turn track before I start playing anything back, to make sure it was all setup right. If you have doubts about what you may be doing with the turn track, or anything else, start your logfile before then and put questions in the comments. You can also make a text or other document file with questions, then zip it with your logfile, and upload the zip file. Just like when you do a chain of logfiles.