That means:
- press [Windows key + R] → type
cmd, press Enter - type
"c:\program files\darktable\bin\darktable" -d common, press Enter (or-d allinstead of-d common)
The logs will be in C:\Users<username>\AppData\Local\Microsoft\Windows\INetCache\darktable\darktable-log.txt.
If your Windows is not English, the paths may be different. For example, instead of Program Files, it could be many other translated paths (Program Files - Wikipedia).