-custom- Widget Sidebar

Hey there,

I got a HTML-based theme, and I have two div-bars in it.
The left div, around 70% of the total width, is full of text.
The right div, around 30% of the total width, should be able to place widgets.

Now, I have tried multiple things, but I can only add widgets at the bottom of the page…

How can I add the ability for users to place widgets in the right div?
I tried the codex of widgets, as well as the sidebars, but I can’t get it working.

Ty !