Noob question about sidebar

Hello all,

I m new and exploring WordPress and i am playing with this great theme, i m comming from prestashop that i can work without problems so please bare with me for this stupid question 😉

This theme is full width but i want to have the sidebar on home but no matter what i add it is not become visible. It also says on widgets page in backend that the sidebar is not active ? How come, can i enable this true a setting so that it become visible.

I also try true the style.css to edit the full width 100% to change to 770px but nothing is changed.

Hope someone can help this noob in wordpress.

Thanks in advance
ysco..