well you could have two scrollable columns using this tutorial:
https://laytheme.com/tutorials/create-a-splitscreen-website.html
this way you have 2 columns. one in the middle and one on the right.
but the one in the middle is the footer page, so it will always be the same content, no matter what page you're on!
using this css as described on my last post can place something to be fixed.
.fixed{
position: fixed;
top: 50px;
left: 30px;
}
maybe that element that uses the class .fixed can be on the far left by using the "left: 30px;" part, making it seem like its the left column.
you may need to do something like:
.fixed{
position: fixed;
top: 50px;
left: calc(-66% + 30px);
}
not sure
other than that there is no way to have 3 columns with content