When the program is installed, the original, default history file (from the downloaded zip file) TPHistory.txt is put into place. While the program is used, the first contact with new station that is not found in the original history file is added to the end of the history file.
We recommend that you practice using the program well in advance of the event, entering practice contacts. Before you start participating in the event you need to delete the log of practice contacts by choosing File, DeleteLog, as shown below.
It will not clear out the TPHistory.txt file. Subsequent use of the program will make use of any new station history data (not in the original history file) that was entered during your earlier use of the program. I tested this by entering a fictitious call sign that I knew was not in the original history file.
Further testing reveals that changes (e.g. chapter #) made during subsequent contacts with any station will not be saved to the history file. However, TPWINLOG will (apparently) consult the tpqsolog.txt file first when subsequent contacts are made with the station whose details were changed on the previous contact entry. Naturally, those changes will be lost when the practice log file is deleted. Any station details that you wish to preserve need to be entered directly into the history file (using a plain text editor) so that they will be found when you start over with a blank log file.
Also, if you do make changes to station data during the event, especially chapter changes, you will want to edit your final log file prior to printing results so that you don't end up with something like 2 chapter numbers recorded for the same call sign.
Please send me email if anything above is not clear or if you have other questions.