When you first open it, you will be asked if you want to save the default settings. Select Yes to save the registry file to the directory of your choice. Later the default settings can be exported from the main interface.
On the simple interface of the software, select and change the font of each item you want to change. For example, select tooltip and drag the slider between 0 and 20 to resize it. Click Apply to complete the change.
Main interface with options to change the system font
After logging out and logging back in, you will see the change. It may take several tries to find the appropriate display size, so don't forget to export and save the most optimal settings to use when needed.