chmod +x mono
/.mono
after running you will go in The following steps :
1-Type the name of new icon theme.
2-choose Mono Dark or Mono Light.
3-generate list of all icon themes in your system.
4-then Type the name of icon theme which you want mono panel icons for it.
5-go to Appearance and click customize button then choose icons tap and you will find new icon theme with whatever name you put in first step.