open clash as a desktop application
modify the path in Clash.desktop
Exec=[path to your clash folder]/cfw
Icon=[path to your clash icon]/logo.png
copy the file Clash.desktop to ~/.local/share/applications for user-wide
cp Clash.desktop ~/.local/share/applications/
or copy the file Clash.desktop to /usr/share/applications for system-wide
cp Clash.desktop /usr/share/applications