Problems with column sizing and responsiveness

Hi all–

I am trying to do a few things with columns on my site that I believe should be quite simple, but for some reason are not working.

First off, here is the link:

On the landing page, I have three columns. I would like these columns to take up the entire viewport, both in terms of width and height, but when when I put in 100 for VH and VW for the columns, it doesn’t work (nor does 100%). Not only does it not fill out the first page, but it starts cutting off columns as it sizes down to other devices. What am I doing wrong?
The second thing I would like to do here is have the entirety of each column be a clickable link, leading to one of the website pages. I dragged in the link block element but for the life of me cannot get the column to drag into it. Tips?

Finally, column sizing is again acting weird on my UX & content strategy page. At the bottom I have created three columns and inserted images into each, but for some reason the columns are really small and they don’t seem adjustable. Ultimately I want the viewer to be able to click any of of the images and have it pop out/take up much more the screen. I assume that using columns plus some kind of an animation will work for this, but if there is a better way, please let me know. Otherwise, any guidance about why column guidance is acting up for me would be much appreciated. Thanks!