Monodevelop doesn't open Unity Documentation. Help!

I started doing the Roll-A-Ball Tutorial, and Ihave followed all instructions, but at the scripting part, I got stuck. I wanted to find the Input with Ctrl + ’ but nothing happened. It didn’t take me to the documentation.
Did it just like in the video, but nothing works. Does someone have a solution?
Thanks.

it doesn’t work for me too, but i’m using visual studio… but you can get the documentation by using the search bar at Unity - Scripting API: