If you already have the software running, here is the standard workflow for fitting a peak:
XPS Peak Fit 4.1 is notoriously picky about file formats. It does not natively read modern raw data files (like .dat or .vgd from newer systems) directly. xps peak fit 41 new download
If you cannot find a legitimate copy of XPS Peak Fit 4.1, it is highly recommended to use modern, actively maintained software. XPS Peak Fit 4.1 was designed for Windows 98/XP and can be unstable on Windows 10/11. If you already have the software running, here