Hi chilibill, for users of GAT and their experience on using it, I suspect the best place to ask is the program's forum.
For the input history, you need to have your history draws in text format. GAT has an AI import mechanism which can understand on its own the structure of the data. What you need to do is to define your lottery game (fields involved) and at the history draws management to click import and select that text file. If the AI for some reason complain, try to remove headers from the text file. If still have issues, please post a sample of that text file.
During the definition of the lottery game you want to import, it is important to enable the dates (I assume it is an official lottery game). If it is drawn once or twice a week, simply select the option "1 per day/week". If you have incorrectly defined the lottery game, the import will fail.
Also there is a lot of usage info on both GAT and WG at the programs' forums, thus checking there for help will certainly help.