Delete the Monika.chr file from there and run DDLC.
Instead of starting a new game, quit DDLC and explore the Characters folder on your desktop. Continue playing the game to receive a letter from Dan Salvato in Act 4.
In the event that you completed the first act earlier, exit the application and use the reset.sh file to reset the progress. Confess your love to Seiori before the second act starts. Then choose Natsuki for the weekend and Yuri after. Thanks to this, you will see cut-scenes for each of the characters for the current day.
Each of them must be dedicated to write two poems for each girl - Yuri, Seiori and Natsuki. First, make sure there is room for three saves. The ending will be much better if you act as follows.
