[Trisquel-users] How to add and select gnome shell themes?

[anandawardhana]

Hello friends,
I've decided to give gnome shell a try (on trisquel 6). I managed to tweak it  
to a greater extent. But I am unable to find how to add and select additional  
themes. I am familiar with a more recent version of gnome (which runs on  
fedora.) And it has an option to add and select gnome themes and shell  
extensions from gnome tweak. But in Trisquel that option is not available.

I've seen some active gnome shell users here. How do you add/remove/select  
themes?

Thanks very much in advance.